SAFETY CONNECTOR ASSEMBLY FIELD OF THE INVENTION [0001] The present disclosure relates to safety connectors for use in medical applications, particularly for use with compression therapy devices. The present disclosure also relates to discriminating safety connector assemblies and, more particularly, to a discriminating safety connector assembly for fluidly coupling at least two lumens capable of forming a non-leaking fluid circuit. BACKGROUND OF THE INVENTION [0002] In a medical environment, many devices have tubing adapted for manual connection in order to provide a fluid connection between devices or between a device and a patient including enteral feeding pumps and intravenous feeding lines. Each of these devices includes one or more connectors that a user or practitioner may inadvertently connect together. This may result in the successful connection of incompatible devices or the supply of fluid or nutrient to an improper intravenous line or a device such as an inflatable bladder used in deep vein thrombosis therapy. Successful connection of incompatible devices may harm patients or damage equipment. [0003] When connecting a medical device to a fluid supply, a non-leaking seal must be made between compatible devices and/or fluid sources. Thus, connections must be designed to provide an adequate seal between sealing surfaces when the devices and/or supply are compatible. Typical devices have a male and female connector that, when pressed together, form a fluid tight seal. The connectors come in different sizes and shapes and typically have 0 rings or gaskets to help create a fluid tight seal. [0004] Examples of a medical device connected to a fluid supply include compression therapy devices that are wrapped around a limb to prevent peripheral edema and conditions that form blood clots such as deep vein thrombosis. These devices typically include at least one air bladder that is sized and shaped for being applied around the limb. The bladder is inflated and deflated to artificially stimulate blood flow throughout the appendage that would normally result from, for example, walking. An example of such a device that is configured for disposal about a foot is shown in U.S. Pub. No. 2005/0187499. Typically, these compression devices are connected to a tube set which provides fluid communication from a pressure source to the compression device. A controller is employed to regulate the flow of fluid from the pressure source to the compression device. (6645797 1):PRW 2 [0005] The compression device, tube set and controller each contain connections for connecting and disconnecting the compression device from the pressure source. It is desirable to avoid erroneous connection of a medical device other than the compression device, for example an intravenous needle, to the pressure source. OBJECT OF THE INVENTION [0006] It is an object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages of the prior art, or to at least provide a useful alternative. SUMMARY OF THE INVENTION [0007] In a first aspect there is disclosed a connector apparatus comprising: a first connector having a housing, an attachment portion, and a coupling portion, the coupling portion including a key, the first connector further comprising a button portion; and a second connector having a housing and an attachment portion, the housing having a mating cavity formed therein for capturing the key of the first connector when the first and second connectors are mated in sealing relation, the mating cavity being laterally opened to the outside of the connector apparatus; wherein depressing the button portion of the first connector deforms the first connector and moves the key laterally outward away from the mating cavity of the second connector. [0008] Preferably, when the first and second connectors are mated in sealing relation and the key is captured in the mating cavity, the key flushes laterally with the housing having the mating cavity. [0009] Preferably, said tube set comprises a tube, the first connector being connected to the tube at a first end thereof and the second connector being connected to the tube at a second end thereof. [0010] In a second aspect there is disclosed a system for providing vascular compression comprising a controller, a tube set, and a compression therapy device wherein the controller and the tube set are connected with a connector apparatus according to the present invention and/or the tube set and the compression therapy device are connected with a connector apparatus according to the present invention. (6645797 1):PRW 3 BRIEF DESCRIPTION OF THE DRAWINGS [0011] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: [0012] FIG. 1 is a perspective of a connector assembly with a first and second connector of the connector assembly engaged; [0013] FIG. 2 is a perspective of the connector assembly with the first and second connector separated; [0014] FIG 2A is a perspective of a "Y" connector releasably attachable to the first or second connector; [0015] FIG. 3 is a perspective longitudinal section of the connector assembly shown in FIG. 1; [0016] FIG. 4 is a perspective of the first connector of the connector assembly shown in FIG. I seen from an end and to a side; [0017] FIG. 5 is a perspective of the first connector seen substantially from the end; [0018] FIG. 6 is a perspective of the connector assembly shown in FIG. I having tubing attached; [0019] FIG. 7 is a perspective of an alternate embodiment of the connector assembly showing two separated connectors with tubing attached; [0020] FIG. 8 is a perspective longitudinal section of the connector assembly shown in FIG. 7; [0021] FIG. 9 is a perspective of another alternative embodiment of the connector assembly with tubing attached; [0022] FIG. 10 is a perspective longitudinal section of the connector assembly as shown in FIG. 9; [0023] FIG. 1 1 is a side elevation of another alternative embodiment of the connector assembly with the first and second connectors engaged; (6645797_1):PRW 4 [0024] FIG. 12 is a longitudinal section of the connector assembly shown in FIG. 11; [0025] FIG. 13 is a perspective of the first connector of the connector assembly shown in FIG. 11; [0026] FIG. 14 is a perspective of the second connector of the connector assembly shown in FIG. I1; [0027] FIG. 15 is a side elevation of another alternative embodiment of the connector assembly with the first and second connectors engaged; [0028] FIG. 16 is a longitudinal section of the connector assembly shown in FIG. 15; [0029] FIG. 17 is a perspective of the first connector of the connector assembly shown in FIG. 15; [0030] FIG. 18 is a perspective of the second connector of the connector assembly shown in FIG. 15; [0031] FIG. 19 is perspective longitudinal section of the engaged first and second connector of the connector assembly shown in FIG. 9; [0032] FIG. 19A is a perspective of the first and second connector separated of the connector assembly shown in FIG. 9; [0033] FIG. 20 is a perspective of an alternative embodiment of the connector assembly with first and second connectors of the connector assembly engaged; [0034] FIG. 21 is a perspective of the connector assembly with the first and second connectors separated; [0035] FIG. 22 is the perspective of FIG. 20 with the first and second housings removed; [0036] FIG. 23 is an exploded perspective of the second connector shown in FIG. 22; [0037] FIG. 24 is a perspective of the first connector assembly shown in FIG 20; (6645797_1):PRW 5 [0038] FIG. 25 is a longitudinal section taken through opposed channels of a non-sealing surface of the first connector shown in FIG. 24 showing attempted attachment of a non-permitted conduit; [0039] FIG. 26 is a perspective of an alternative embodiment of the first connector assembly; [0040] FIG. 27 is a longitudinal section taken through opposed channels of a non-sealing surface of the first connector shown in FIG. 26 showing attempted attachment of a non-permitted conduit; [0041] FIG. 28 is a perspective of a first connector of an alternate embodiment of the connector assembly; [0042] FIG. 29 is a perspective of a second connector of the connector assembly of Fig. 28 attached to tubing; [0043] FIG. 30 is a longitudinal section of the connector assembly of FIGS. 28 and 29 with the first and second connectors of the connector assembly engaged; [0044] FIG. 31 is a longitudinal section taken through opposed channels of a non-sealing surface of the first connector in FIG. 28 showing attempted attachment of a non-permitted conduit; [0045] FIG. 32 is a perspective of a compression therapy device showing an inflatable bladder and an enlarged view of the connector; [0046] FIG. 33 is a perspective of a compression therapy device controller with an enlarged view of the connector; and [0047] FIG. 34 is an enlarged perspective of a tube set. [0048] Corresponding reference characters indicate corresponding parts throughout the drawings. (6645797_1):PRW 6 DESCRIPTION OF THE PREFERRED EMBODIMENTS [00491 Referring now to the drawings, a connector assembly 30 constructed according to the principles of the present invention is shown in FIGS. I and 2 to comprise a first connector 36 and a second connector 38. As described more fully hereinafter, the first and second connectors 36, 38 are capable of discriminating connection to preferentially achieve fluid-tight connection of the connectors, and avoid fluid-tight connection with non-complying connectors. The connector system 30 may be used, for example, to connect a controller 2 to a compression therapy device I for cyclically supplying air pressure to a bladder 4 of the device (see, FIGS. 32 and 33). The compression therapy device I illustrated in FIG. 32 is of the type which is applied to the foot for repeatedly compressing the foot to force blood out of the foot and discourage pooling of blood in the foot that can lead to clots. Although a foot compression therapy device 1 is illustrated, other types of compression therapy devices can be employed, such as those that are applied to the leg. Other examples of foot and leg devices are disclosed in U.S. Patent Nos. 5,626,556 and 5,795,312. Moreover, the connector assembly 30 can be used for other types of medical fluid connections such as the connection of an enteral feeding bag to a patient. [0050] In the illustrated example, a tube set 20 (FIG. 34) is used to selectively interconnect the compression therapy device I and the controller 2. The first connector 36 is attached to a first tubing 32 of the tube set 20, and the second connector 38 is attached to a second tubing 34 extending from the bladder 4 of the compression therapy device 1 (FIG. 32). A third connector 10 having substantially the same construction as the first connector 36 is attached to the controller 2 (FIG. 33), and a fourth connector 26 having substantially the same construction as the second connector 38 is attached to the opposite end of the tubing 32 of the tube set 20 (FIG. 34). In order to make fluid connection for delivering of pressurized air from the controller 2 to the compression therapy device 1, the fourth connector 26 of the tube set 20 is engaged with the third connector 10 of the controller, and the first connector 36 of the tube set is engaged with the second connector 38 of the compression therapy device. Because of the structural identity of the first connector 36 and third connector 10, and of the second connector 38 and the fourth connector 26, only the first and second connectors will be described in detail hereinafter. [0051] Referring to FIGS. 1-6, the first connector 36 has an attachment portion 40 that accepts the tubing 32. However, the attachment portion 40 could be directly connected to an object other than tubing, such as the third connector 10 is directly connected to the controller 2 (FIG. 33). The second connector 38 has an attachment portion 80 and a receptacle 78. The receptacle 78 (6645797 l):PRW 7 has a roughly hourglass shape, so the user can grasp and hold the connector assembly 30 and to aid the user in engaging the second connector 38 to the first connector 36, as shown in Figure 1. [0052] Referring to Figure 2, a coupling portion 42 of the first connector 36 has a first end 44 and a second end 46. The second end 46 is suitably attached to the attachment portion 40, such as by solvent bending or RF welding, or may be formed as one piece of material with the attachment portion. The attachment portion 40 is sealingly received in the tubing 32 of the tube set 20 (FIG. 34). The coupling portion 42 includes a sealing surface 48 and a non-sealing surface 52. The sealing surface 48 extends around the perimeter of the coupling portion 42 at the second end 46. The shape and contour of the coupling portion 42 is not restricted to that of the illustrated embodiment, so long as the coupling portion can engage and form a seal with the second connector 38, as will be described. The non-sealing surface 52 has a greater diameter than the sealing surface 48. A number of circumferentially spaced channels 58 in the non sealing surface 52 extend lengthwise of the first connection 36. Two of the channels 58 communicate with openings 60 extending radially through the first connector 36 to an inner surface 54 thereof. The channels 58 and openings 60 operate to inhibit the formation of a sealing connection. [0053] The receptacle 78 of the second connector 38 has an interior surface 74 and an annular shoulder 75 at the inner end of the interior of the receptacle (FIG. 3). The shoulder 75 defines a stop surface that limits the distance the first connector 36 can be inserted into the receptacle 78 and axially positions the first connector 36 with respect to the receptacle 78. An annular sealing flange 76 projects radially inward of the inner surface 74 of the receptacle 78 near the open end of the receptacle. As illustrated, the sealing flange 76 is formed as one piece of material with the receptacle 78. However, a sealing member (not shown) may be formed separately from the receptacle (e.g., as an O-ring) and secured to the receptacle such as by being received in a circumferential groove formed in the inner surface of the receptacle. [0054] The user must push, in the direction of the arrow "A" in FIG. 2, the first end 44 of the first connector 36 into the receptacle 78 of the second connector 38, such that the non-sealing surface 52 passes beyond the sealing flange 76. Unless the user pushes the connectors 36, 38 together, a fluid tight seal will not form because of longitudinal channels 58 disposed about the outer surface of coupling portion 42. The sealing flange 76 cannot conform into the channels 58 that extend past the flange allowing fluid to pass the flange on the non-sealing surface 52 of the first connector 36. However, when the sealing surface 48 moves into registration with the (6645797_1):PRW 8 sealing flange 76, the flange is able to sealingly conform to the sealing surface to make a fluid tight connection with the sealing surface. [0055] The open space defined by the longitudinal channels 58 prevents flush engagement of coupling portion 42 with the surface of a non-compliant connector or fluid conduit (lumen). The longitudinal channels 58 may have widths, depths, or lengths other than illustrated herein. One or more longitudinal channels 58 may be oriented parallel, offset, or undulating with the longitudinal axis of the connector 30. The longitudinal channels 58 can be replaced with a raised surface or roughness on the non-sealing surface 52. In addition, the openings 60 defined through a wall 62 help prevent a fluid seal between the first connector 36 and a non-compliant connector. An opening 60 is not limited to size and shape provided the opening leaks with a non-compliant connector attached to the first connector 36. One or more openings 60 diametrically opposed about the wall 62 facilitate leakage with a non-compliant connector. [0056] An inner surface 54 of the first connector 36 and inner surface 74 of the second connector 38 form a fluid pathway therethrough. The inner surfaces (54, 74) are formed to pass fluid according to the particular flow requirements of a medical system such as the controller 2 and compression therapy device 1. Attachment portion 40 or attachment portion 80 is not restricted to one port. A "Y" connector 84 (FIG. 2A) is releasably attachable to the attachment portion (40, 80) of either connector 36, 38 to increase the number of fluids or divert pressurized air to more than one bladder, in the case of compression sleeve. [0057] Figure 3 illustrates the connector assembly engaged, without the tubing 32, 34 attached. In use, the first tubing 32 (not shown in FIG. 3) is sealingly attached to an inner surface 82 of the attachment portion 80. The second tubing (not shown in FIG. 3) is attached to attachment portion 40. The point contact "P" seals the connector assembly 30 upon contact between the sealing flange 76 and the sealing surface 48 of the first connector 36. The tubing 32, 34 is attached in a suitable manner such as by using solvent bonding, RF welding, or other attaching means known in the art. [0058] Figures 4 and 5 show a transverse wall 68 at the first end 44 of the first connector 36. The transverse wall 68 has a longitudinal cavity 70 across its face. The transverse wall 68 extends along the longitudinal axis for substantially the length of the non-sealing surface 52 and inhibits the insertion of tubes or other connectors (not shown) into the first connector 36. One or more longitudinal cavities 72 extend along the inner surface 56 at the first end 44. The non (6645797_l):PRW 9 sealing surface 52 has a first face 64 with transverse cavities 66 disposed at spaced locations around the perimeter of the first face 64. Each transverse cavity 66 connects to a corresponding one of the longitudinal channels 58 formed in the wall 62 of the coupling portion 42 of first connector 36. This allows fluid to escape between the first connector 36 and a non-compliant connector. Likewise, the openings 60 allow fluid to escape when a seal is not formed with the sealing surface 48. The number and arrangement of channels 58, openings 60 and cavities 66 may be other than described without departing from the scope of the present invention. [0059] The cavities 66 prevent a seal between the first face 64 and a surface of a non-compliant connector. Each cavity 66 aligns with its corresponding outer longitudinal channels 58 to provide a path for leakage when the first connector 36 is inserted into a non-compliant connector. The transverse wall 68 prevents inserting a non-compliant connector into the first connector 36. The cavity 70 helps prevent a sealing surface between the first face 64 and a surface of a non complaint connector. Likewise, inner longitudinal cavities 72 and the openings 60 though the wall 62 help prevent sealing with a non-compliant connector on the inside or outside of the first connector 36. The open spaces defined by the cavities 66 prevent flush engagement with coupling portion 42 and a surface of a non-compliant connector. A cavity or channel (66, 70, 72, 58) is not limited to a specific width, depth, or length. A cavity or channel (66, 70, 72, 58) is not restricted to orientation and can be parallel, offset or undulating. The present invention is not restricted to one non-sealing surface 52 or one sealing surface 48. [0060] Figures 7 and 8 illustrate an alternative connector assembly 130. Parts of the connector assembly 130 generally corresponding to those of the connector assembly 30 will be given the same number, plus "100." A first connector 136 of the connector assembly 130 has a first end 144 and a second end 146. Located generally between the first and second ends 144, 146 is a sealing surface 148. The coupling portion 142 is rectangular with rounded corners and sized to fit into the opening of a second connector 138, in the direction of arrow "A". The second connector 138 defines a receptacle in a housing of the second connector to receive the first connector 136. An outwardly flared non-sealing surface 152 is located at the open end of the second connector 138. Triangular channels 158 in the non-sealing surface provide fluid communication paths to locations outside the connectors 136, 138 to inhibit sealing. [0061] The user holds the second connector 138 using raised ribs 178 to grip and insert the first connector 136 into the second connector 138. In addition to functioning as grips, the ribs 178 also prevent a sealing connection between the second connector 138 and a tube or the like (not (6645797 ):PRW 10 shown) received over the exterior of the second connector. The first connector 136 is inserted with its first end 144 passing beyond a sealing flange 176 located inside the second connector 138. The resilient sealing flange 176 conforms to the sealing surface 148 to form a fluid tight seal, after the sealing surface 148 passes beyond the non-sealing surface 152 and engages the flange 176. The user stops applying force when the face of the first end 144 abuts a shoulder 175 a distance beyond the sealing flange 176 of the second connector 138. A bar 181 is located at the inner end of the second connector 138 to inhibit a tube (not shown) from sealingly abutting a first tube 132 inserted inside an attachment portion 180 of the second connector. [0062] The first tubing 132 forms a sealing interference fit with the inner surface 182 of the attachment portion 180. A second tubing 134 is inserted over an attachment portion 140 (FIG. 8), at the second end 146 of the coupling portion 142. The first and second tubings 132, 134 are attached in suitable ways to the first and second connectors 136, 138. This forms a fluid conduit as part of a medical system when properly connected. [0063] Figures 9 and 10 illustrate a connector assembly 230 comprising a key 252 and a mating cavity 290. Parts of the connector assembly 230 corresponding to those of the connector assembly 30 are given the same reference numeral, plus "200." When the key 252 is positioned in the cavity 290, the user has established a fluid-tight seal within the connector assembly 230. The connector assembly 230 comprises a first connector 236 and a second connector 238. The first connector 236 has a tubular attachment portion 240 secured to an interior of a housing 241 of the first connector. The attachment portion 240 can be sealingly received in a (second) tubing 234. The second connector 238 has an attachment portion 280 that can attach the second connector to a (first) tubing 232. The second connector 238 includes a housing 281 that mounts the attachment portion 280 by way of a flange 283 of the attachment portion. A gasket 276 (broadly, "a sealing member") mounted by the housing 281 is generally tubular in shape and includes ears 276a that are received in correspondingly shaped openings 277 in the housing 281. The gasket 276 is received around and sealingly engages an exterior surface of the attachment portion 280 axially inward of the mounting flange 283. [0064] Coupling portion 242 is slidingly and sealingly received by a first end of second connector 238 into the gasket 276 to form a sealing connection between the first and second connectors. The key 252 snaps into the mating cavity 290 to releasably lock the first and second connectors 236, 238 is sealing connection. To release the first connector 236, the user depresses a button 286, with raised edges, and pulls the first connector 236 from the second connector 238, (6645797 1I:PRW I1 while holding the second connector 238. Depressing the button 286 deforms the first connector and moves the key 252 laterally out of the cavity 290. The key 252 prevents engagement with a non-compliant connector (not shown). [0065] An alternate embodiment of a keyed connector assembly 530 illustrated in Figures 19 and 19A is similar to the keyed connector assembly 230 of Figures 9 and 10. Parts of the connector assembly 530 corresponding to those of the connector assembly 30 are given the same reference numeral, plus "500." The first connector 536 comprises a key 552, guide flanges 553 and an inner rigid lumen or conduit 548 including an attachment portion 540. The second connector 538 comprises a mating cavity 590, an inner sealing member 588, and finger grips 578 An attachment portion 580 located within the second connector 538 includes an inner part 580a that is sealingly attached to the sealing member 588, and an outer part 580b that can be attached to tubing (not shown). In operation, the user grips the second connector 538 at the finger grips 578, grips the first connector 536 and then pushes the key 552 toward the cavity 590 until it snaps into the cavity. The flanges 553 engage the second connector 538 and help guide the first connector 536 into sealing engagement with the second connector. The inner end of the conduit 548 is received in the sealing member 588 and seals with the sealing member by engagement with an annular protrusion 576 in the sealing member. In this way, a sealing connection of the first and second connectors 536, 538 can be made. [0066] Figures 11-14 illustrate still another alternate embodiment of a connector assembly 330. Parts of the connector assembly 330 corresponding to those of the connector assembly 30 are designated by the same reference numerals, plus "300." Connector assembly 330 comprises a first connector 336 (FIG. 13), and a second connector 338 (FIG. 14). First connector 336 has an attachment portion 340 (FIG. 12) that accepts tubing (not shown) on the inner surface 341 of the attachment portion 340. The second connector 338 (FIG. 14) has an attachment portion 380 at a first end and a cap 374 at the second end. A second tubing (not shown) can be received on attachment portion 380. Spaced a distance from the second end is a deformable O-ring 376 around the perimeter of the cap 374. The O-ring 376 is releasably attached to the cap 374. It will be understood that a sealing member can be formed in any suitable manner such as an 0 ring (as shown) or a raised surface of deformable plastic. [0067] The first connector 336 further comprises a coupling portion 342 with at least one longitudinal channel 372 therethrough (FIG. 13). A plurality of non-sealing surface 352 areas (FIGS. 12 and 13) are disposed on the inside of the coupling portion 342. The non-sealing (6645797_l):PRW 12 surfaces 352 have longitudinal channels 358 disposed on the inner surface of the first connector 336 to prevent a fluid seal with a non-compliant connector. The axially inner longitudinal channels 358 are also disposed on both sides of a groove 349 that defines the sealing surface 348 (FIG. 13). At the face of the coupling 342 are disposed a plurality of longitudinal channels 372 (FIG. 13). The open space defined by the channels 372 prevents the coupling portion 342 from forming a fluid seal with a surface of a non-compliant connector. [0068] In operation, the user inserts the cap 374 into the opening at the coupling portion 342. The O-ring 376 is deformed as it moves over the non-sealing surfaces 352 under the force of the user. The O-ring 376 comes to rest in the groove 349 and engages the sealing surface 348 (FIG. 13), to form a fluid tight seal. [0069] Figures 15-18 illustrate a further embodiment of a connector assembly 430. Parts of the connector assembly 430 corresponding to those of the connector assembly 30 are given the same reference numerals, plus "400." Connector assembly 430 includes a first connector 436 and a second connector 438. The first connector 436 has an attachment portion 440 that can be attached to a lumen (not shown) which fluidly communicates with a fluid source. A lumen (or tubing) is received on an outer surface of attachment portion 440 and forms a fluid-tight seal therewith. The first connector 436 has a coupling portion 442 comprising a sealing surface 448 and a pair of non-sealing surfaces 452 and each non-sealing surface 452 having longitudinal channels 458 (FIG. 17) disposed on the inner and outer surfaces of the coupling portion 442. The longitudinal channels 458 are disposed on either side of the sealing surface 448. The longitudinal channels 458 prevent a sealing engagement with the coupling portion 442 by a non compliant connector. A longitudinal channel 458 can be oriented anywhere along the perimeter of the coupling portion 442 and can be of varying length, width or depth. A generally annular detent 479 (broken by channels 458) extends around the first connector 436. [0070] The non-sealing surface 452 includes a first face 464. The first face 464 includes a transverse wall 468 that extends across the diameter of coupling portion 442. Transverse wall 468 is configured to prevent sealing engagement of the surface of coupling portion 442 with a non-compliant connector. [0071] The second connector 438 comprises an attachment portion 480, a cap 474, an O-ring 476 inside the cap and sealingly mounted on the cap, and a flex collar 477 (FIGS. 16 and 18). In operation, the user pushes the second connector 438 onto the coupling portion 442, with the first (6645797 I):PRW 13 face 464 entering the opening of the second connector 438, at the flex collar end. The O-ring 476 engages the leading non-sealing surface 452 and does not establish a sealing connection with the non-sealing surface because of the channels 458. The O-ring 476 next engages the sealing surface 448 as the first connector 436 is advanced farther into the second connector 438 and establishes a sealing connection between the first and second connectors. The detents 479 of the first connector 436 are received in annular grooves 478 on the interior of the flex collar 477. The flex collar, which has been deflected from its relaxed position, bears against the detents 479 and holds them in the grooves 478 for securing the first and second connectors 436, 438 together. [0072] Figures 20-25 illustrate a further embodiment of a connector assembly 630. Parts of the connector assembly 630 corresponding to those of the connector assembly 30 are given the same reference numerals, plus "600." The connector assembly 630 includes a first connector 636 and second connector 638 The first connector 636 includes a first housing 657, attachment portion 640, and coupling portion 642 and the second connector 638 includes a second housing 659, attachment portion 680, and receptacle 678. The first and second housings 657, 659 are removed in Figures 22 and 23 to better illustrate other features of the first and second connectors 636, 638. The first connector 636 may be integral with or secured to another object or device such as a wall 643 (only a fragmentary portion being illustrated) of the housing of a controller like the controller 2 shown in FIG. 33. The attachment portion 640 of the first connector 636 accepts tubing (not shown, but like medical tubing 32) that extends from the pump within the controller. However, the attachment portion 640 could be directly connected to an object other than tubing [0073] Referring to Figure 22, the coupling portion 642 of the first connector 636 has a first end 644 and a second end 646. The second end 646 is suitably attached to the attachment portion 640, such as by solvent bonding or RF welding, or may be formed as one piece of material with the attachment portion. The attachment portion 640 may be sealingly received in tubing (e.g., tubing 32 of the tube set 20 (FIG. 34)). The coupling portion 642 includes a sealing surface 648 and a non-sealing surface 652. The non-sealing surface 652 is closer to the free end of the first connector 636 than the sealing surface 648. The sealing surface 648 extends around the perimeter of the coupling portion 642 at the second end 646. The shape and contour of the coupling portion 642 is not restricted to that of the illustrated embodiment, so long as the coupling portion can engage and form a seal with the second connector 638, as will be described. The non-sealing surface 652 has a greater diameter than the sealing surface 648. A number of circumferentially spaced channels 658 in the non-sealing surface 652 extend lengthwise of the (6645797 I):PRW 14 first connector 636. The channels 658 operate to inhibit the formation of a sealing connection with an interior surface of medical tubing. [0074] The second connector 638 has a deformable O-ring 663 at the end of the receptacle 678 opposite the attachment portion 680, which is captured by a cap 655. Referring now to Figure 23, the cap 655 fits over the O-ring 663 and makes a snap connection with a tapered end 665 of the receptacle 678 to capture the O-ring between the cap and the face 667 of the receptacle. Once captured, the O-ring 663 protrudes radially inward from between the end face 667 of the receptacle 678 and the cap 655 such that the O-ring can sealingly engage the sealing surface 648 of the first connector 636 when the first connector 636 is received in the second connector 638. The attachment portion 680 of the second connector 638 tapers in diameter toward its middle to facilitate gripping of the second connector assembly 639. The attachment portion 680 may sealingly receive generic tubing (e.g., tubing 32 of the tube set 20 (FIG. 34)). [0075] Referring to Figures 20 and 21, the second connector 638 includes a key 611 having a projecting member 621. The first connector 636 includes a mating cavity 613. To form a seal between the first connector 636 and the second connector 638, the user must push the first end 644 of the first connector through the O-ring 663 and into the receptacle 678 of the second connector 638, such that the non-sealing surface 652 passes beyond the O-ring. When the key 611 of the second connector 638 639 is positioned in the mating cavity 613 of the first connector 636 to such an extent that the projecting member 621 abuts the first housing 657, the sealing surface 648 has engaged the O-ring 663. Abutment of the projecting member 621 and the first housing 657 prevents separation of the first connector 636 and the second connector 638. To release the second connector 638, the user depresses the projecting member 621 and pulls the first connector 636 from the second connector 638, while holding the second connector. Depressing the projecting member 621 moves the projecting member out of the mating cavity 613. [0076] Referring to Figures 24 and 25, the first housing 657 of the first connector 636 includes a floor 671. The coupling portion 642 projects outward from the floor 671. Standoff ribs 675 that project outward from the housing floor 671 are circumferentially spaced about the coupling portion 642. The end of each standoff rib 675 adjacent the coupling portion 642 is attached to a connecting segment 681 that circumferentially surrounds the coupling portion. Bleed passages generally indicated at 679 are defined beyond the connecting segments 681 and between the ribs 675 and floor 671. The bleed passages 679 extend past the end face of a conduit such as generic (6645797 I):PRW 15 medical tubing, when the conduit is fully inserted onto the coupling portion 642 that allows fluid to be bled around the coupling portion to prevent a fluid-tight seal. The direction and pathway of flow is generally indicated by arrow "A" (FIG. 25). The bleed passages 679 prevent successful fluid-tight connection between the coupling portion and medical tubing MT (a "non-permitted conduit") when the end face of the medical tubing is pushed all the way into the first housing 657 as illustrated in FIGS. 25. In this condition, a typical controller can sense the absence of the fluid tight connection and initiate an alarm. [0077] Figures 26 and 27 illustrate a further embodiment of the first connector 736. Parts of the first connector 736 corresponding to those of the connector 636 are given the same reference numerals, plus "100." Bleed passages 779 are formed in the first connector 736 and located generally adjacent the floor 771 of the housing 757 for bleeding fluid around the coupling portion 742. Referring now to Figure 26, the bleed passages 779 open radially outward of the coupling portion 742 at a first opening and extend axially through the housing floor 771 and open from the first connector at the side of the floor opposite the first opening. A non-sealing surface 752 of the coupling portion 742 holds conventional medical tubing MT (a "non-permitted conduit") from sealing with the sealing surface 748. An end face of the tubing MT may seal with the floor 771. However, the bleed passages 779 formed in the sealing surface 748 are not sealed. Thus, air in the medical tubing MT may pass through the channels 758 in the non-sealing surface 752, along the sealing surface 748 and out the bleed passages 779 as indicated by arrow "B" (FIG. 27). Therefore, no fluid-tight connection can be made with standard medical tubing MT, even if the end face of the tubing otherwise seals with the floor 771. [0078] Figures 28-31 illustrate a further embodiment of a connector assembly 830. Parts of the connector assembly 830 corresponding to those of the connector assembly 30 are given the same reference numerals, plus "800." The connector assembly 830 comprises a first connector 836 and a second connector 838 (FIGS. 28 and 29). The first connector 836 has a tubular and barbed attachment portion 840 secured to a gripping portion 841 of the first connector and located in an interior of the gripping portion (FIG. 30). The attachment portion 840 can be sealingly received in tubing 834. However, the attachment portion 840 could be directly connected to an object other than tubing, in the same way as the third connector 10 is directly connected to the controller 2. The second connector 838 has an attachment portion 880 that can attach the second connector to generic tubing 832 (e.g., like tubing 32 of the tube set 20 (FIG. 34)). (6645797 1):PRW 16 [0079] The second connector 838 includes a receptacle 878. The receptacle 878 mounts to the attachment portion 880 by way of a flange 883. The receptacle 878 has an interior surface 874 and an annular shoulder 875 at the inner end of the interior of the receptacle (FIG. 30). The shoulder 875 defines a stop surface that limits the distance the first connector 836 can be inserted into the receptacle 878 and axially positions the first connector 836 with respect to the receptacle 878. [0080] The surface of the gripping portion 841 of the first connector 836 and the surface of the attachment portion 880 of the second connector 838 include raised ridges 814, 824. The raised ridges 814 of the first connector 836 include two generally opposed parentheses shaped first ridges 814a that extend generally lengthwise of the first connector and two flattened U-shaped second ridges 814b spaced lengthwise of the first connector and located between the first ridges (FIG. 28). Likewise, the raised ridges 824 include first ridges 824a and second ridges 824b shaped and arranged in the same way as the first ridges 814a and second ridges 814b (see, FIG. 29). In the illustrated embodiment, the first and second ridges 814a, 814b and 824a, 824b are arranged to define channels 822, 828 (respectively) for the passage of air along the connector 836, 838. The raised ridges generally indicated at 814 and 824, respectively, prevent a fluid tight seal from forming when generic medical tubing is placed over the surface of the gripping portion 841 or of the attachment portion 880. Channels 822, 828 defined by the raised ridges 814, 824 carry fluid away from the connectors 836, 838 in a direction generally indicated by arrow "A" if such tubing (not shown) is placed over the connectors thereby inhibiting a fluid tight connection of either of the connectors 836, 838 with the medical tubing. The second ridges 814b, 824b help to prevent highly conforming tube material from sealing with and between the first ridges 814a, 824b. [0081] It is to be understood that the ridges 814 and 824 may have shapes and arrangements that are different from what is illustrated and different from each other within the scope of the present invention. As shaped and arranged in the illustrated embodiment, the ridges 814, 824 provide for the passage of air, but also facilitate gripping the connector 836, 838. In the illustrated embodiment there are ridges (not shown) just like the ridges 814, 824 that may be seen in FIGS. 28 and 29, but which are located in the opposite sides of the connectors 836, 838. [0082] Referring to Figure 28, the gripping portion 841 of the first connector 836 has a flange 815 formed at a distal end. The first connector 836 includes a coupling portion 842 and a floor 871. The diameter of the floor 871 is generally the same as the diameter of the flange 815. The (6645797 1l:PRW 17 floor 871 and flange 815 include bleed passages 817 at their perimeters to prevent a fluid-tight seal when medical tubing is placed over the perimeters of the flange and floor. Another pair of bleed passages (not shown) like bleed passages 817 are located at the opposite side of the connector 836. It will be understood that any number of bleed passages may be employed within the scope of the present invention. [0083] The first connector 836 includes a coupling portion 842 that projects outward from the floor 871. Standoff ribs 875 that project outward from the floor 871 are circumferentially spaced about the coupling portion 842. Bleed passages generally indicated at 879 are defined between the ribs 875 and floor 871. The bleed passages 879 are recessed from the ribs 875 and communicate with bleed passages 817. If a medical tube MT that is too small to receive the entire connector 836 therein is pushed over the coupling portion 842 as illustrated in FIG. 31, an end of the tubing engages the ribs 875 and is held off the floor 871. Air may flow out of the tube, into the bleed passages 879 to bleed passages 817 or directed radially outward of the first connector 836. The direction and pathway of flow is generally indicated by arrow "A" (FIG. 31). The bleed passages 817, 879 prevent successful fluid-tight connection between the coupling portion 842 and medical tubing when the end face of the medical tubing is pushed all the way to the floor 871. [0084] The coupling portion 842 includes a sealing surface 848 and a non-sealing surface 852. The non-sealing surface is closer to the free end of the first connector 836 than the sealing surface 848. The sealing surface extends around the perimeter of the coupling portion 842. The shape and contour of the coupling portion 842 is not restricted to that of the illustrated embodiment, so long as the coupling portion can engage and form a seal with the second connector 838, as will be described. The non-sealing surface 852 has a greater diameter than the sealing surface 848. A number of circumferentially spaced channels 858 in the non-sealing surface 852 extend lengthwise of the first connector 836. The channels 858 operate to inhibit the formation of a sealing connection of the coupling portion 842 with an interior surface of medical tubing. [0085] The second connector 838 has a deformable O-ring 863 at the end of the receptacle 878 opposite the attachment portion 880. The O-ring 863 protrudes radially inward and is positioned axially so that the O-ring can sealingly engage the sealing surface 848 of the first connector 836 when the first connector 836 is received in the second connector 838 to make a fluid-tight connection. In this way, essentially only desired connections are allowed. (6645797 1):PRW