IE960463A1

IE960463A1 - A diverter for a computer, and a computer comprising the¹diverter

Info

Publication number: IE960463A1
Application number: IE960463A
Authority: IE
Inventors: Henry Francis Lynam; Henry Conleith Lynam
Original assignee: Laserform Holdings Limited
Priority date: 1995-06-26
Filing date: 1996-06-25
Publication date: 1996-12-30
Also published as: GB9613270D0; IES69756B2; GB2302746B; GB2302746A; IES950458A2

Abstract

A diverter device (8, 11, 12) for locating in a computer (1) for communicating applications software (2) with one of a modem port (5) and an ISDN port (10) for communicating the computer (1) with another computer on a PSTN (3) or an ISDN (9). The diverter device (8, 11, 12) is transparent to the applications software (2) and is located between the applications software (2) and a COMM driver (6), and an identifying and diverting part (II) of the diverter device (8) sits on top of the COMM driver (6). The identifying and diverting part (11) of the diverter device (8) sits on top of the COMM driver (6). The identifying and diverting part (II) determines whether communication is to be through the modem port (5) or the ISDN port (10), and diverts commands and data from the applications software (2) to the appropriate port (5, 10). Commands and data for the modem port (5) are passed directly through the identifying and diverting part (II) to the COMM driver (6). Commands and data for the ISDN port (10) are diverted by the identifying and diverting part (11) through the ISDN driver (12) to the ISDN port (10).

Description

A diverter for a computer, and a computer comprising the diverter The present invention relates to a diverter for locating in a computer for selecting one of a modem port and an ISDN port of the computer in response to applications software resident in the computer, whereby the applications software is suitable for communicating through a modem with another computer over a public switched telephone network (PSTN), the diverter device being suitable for allowing the applications software to communicate with another computer over an integrated services digital network (ISDN) through the ISDN port of the computer. The invention also relates to a computer comprising the diverter, and to a method for operating a computer for allowing applications software resident therein to communicate with another computer over the ISDN.

Where applications software for communicating a computer on a PSTN is resident in a computer, the applications software is, in general, only suitable for communicating through a modem on PSTN. Attempts have been made to provide such applications software with a facility for communicating with other computers through an ISDN, however, to date, while such attempts have met _25 with limited success I ; jQ p”.-»? if· UNCTION in general, it is not possible to JNL Να.Δ??...........OF run applications software which is provided for operating over a modem on an ISDN, and achieve transfer of data at the relatively rapid rate at which ISDN facilitates. In general, in order to enable such applications software to communicate on an ISDN, it is necessary to provide additional software in the computer. Such additional software, in general, is provided in the computer at the same level as the applications software, and thus, cannot operate simultaneously with the applications software. In Windows 3.1 operating systems applications software runs non-preemptively, therefore, one applications software must yield control to allow another applications software to run. In the case of COMM software, where the applications do not yield control until data has been sent out through the modem, the applications software must wait to perform correctly when the system requires two applications software to run simultaneously.

There is therefore a need for a method and a diverter for use in a computer which enables applications software designed for use with a modem on a PSTN to be used on an ISDN, while at the same time enabling full advantage to be taken of the high speed data transfer facilitated by ISDN. There is also a need for a computer comprising such a diverter and operating under such a method.

The present invention is directed towards providing such a diverter, a method and a computer.

According to the invention there is provided a diverter for locating in a computer for selecting one of a modem port and an ISDN port of the computer in response to applications software resident in the computer, the applications software being of the type for communicating the computer through the modem port for permitting communication with a PSTN through a modem, and the computer being of the type comprising a COMM driver for communicating the applications software with the modem port, the diverter being locatable in the computer between the applications software and the COMM driver, and being transparent to the applications software, and the diverter comprising a means for allowing commands and data to pass therethrough uninterrupted to the COMM driver where data is to be sent by the applications software through the modem port, a means for diverting commands and data to be sent to the ISDN port, an ISDN interface means for interfacing the applications software with an ISDN, and for sending data over the ISDN, and a conversion means for converting commands in modem format to the equivalent commands associated with ISDN, the diverter l 96 046 3 being operable simultaneously with the applications software for communicating the applications software with the ISDN.

In one aspect of the invention the means for allowing the commands and data to pass through the diverter to the COMM driver and for diverting commands and data to the ISDN port are responsive to signals identifying the ISDN port and the modem port, respectively, received from the applications software.

In another aspect of the invention the means for allowing commands and data to pass through the diverter to the COMM driver and for diverting commands and data to the ISDN port comprise a reading means for reading commands from the application software, and for reading the identity of the port specified by the applications software through which the commands and data are to be sent.

In another aspect of the invention the reading means comprises a means for reading an OPENCOMM command from a Windows operating system for opening communications with the PSTN or the ISDN.

In a further aspect of the invention the reading means comprises a means for reading a CLOSECOMM command for »60463 returning the diverter to a waiting mode for awaiting the next OPENCOMM command.

In one embodiment of the invention the ISDN interface means comprises an ISDN driver. Preferably, the ISDN driver comprises a means for initialising memory locations, and a means for setting up a channel in the ISDN in response to an ATD command from the applications software. Advantageously, the means for setting up a channel in the ISDN sets up one B-channel on a line in the ISDN. Ideally, the means for setting up a channel in the ISDN sets up two B-channels on a line in the ISDN.

Preferably, the diverter comprises a means for packing data to be sent on the ISDN into data packets.

Advantageously, the data packets are sequentially numbered and where two B-channels are set up, substantially half the data packets are sent on one Bchannel and the other half of the data packets are sent on the other B-channel.

In one embodiment of the invention the diverter comprises an identifying and diverting part for identifying commands and data from the applications software and for diverting commands and data to the ISDN port, and an ISDN driver for driving the ISDN 6 0 4 6 3 »< port, the identifying and diverting part of the diverter being adapted to sit just above the COMM driver between the applications software and the COMM driver, and the ISDN driver being adapted to sit above the ISDN port between the identifying and diverting part and the ISDN port.

In one embodiment of the invention the diverter is suitable for use in a computer in which the ISDN port is CAPI (Common-ISDN-API) compliant and supports versions 1.1 or 2.0.

Additionally, the invention provides a computer comprising the diverter according to the invention wherein the diverter is located in the computer between the applications software and the COMM driver.

In one aspect of the invention the identifying and diverting part of the diverter is located to sit just above the COMM driver, and the ISDN driver is located to sit above the ISDN port.

In another aspect of the invention the applications software and the diverter are operable simultaneously in the computer.

Further the invention provides a method for operating a computer under the control of applications software and the diverter according to the invention wherein the diverter on receiving a command from the applications software identifying one of a modem port and an ISDN port, selects the appropriate port and communicates the applications software with the selected port.

In one embodiment of the invention the diverter converts a command in modem format received from the applications software into ISDN format for sending over the ISDN.

In another embodiment of the invention commands and data from the applications software to be sent to the modem port are allowed to pass through the diverter directly to the COMM driver.

The invention will be more clearly understood from the following description of a preferred embodiment thereof which is given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a block representation of a computer according to the invention comprising a diverter also according to the invention located therein, Fig. 2 is a block representation of a flowchart illustrating the operation of the diverter of Fig. 1, and Fig. 3 is a block representation of a flowchart which also illustrates the operation of the diverter of Fig. 1.

Referring to the drawings and initially to Fig. 1, there is illustrated in block representation a computer according to the invention indicated generally by the reference numeral 1, which comprises a modem port 2 for communicating the computer 1 through a modem 4 with a PSTN 5 for facilitating exchange of data between the computer 1 and another computer (not shown) connected to the PSTN 5. The computer 1 also comprises a CAPI compliant ISDN port 6 for communicating the computer 1 with an ISDN 7 for facilitating exchange of data between the computer 1 and another computer (not shown) connected to the ISDN 7. Applications software 8 is resident in the computer for communicating with such another computer (not shown) over the PSTN 5 through the modem 4. A COMM driver 10 which is implemented in software is resident in the computer 1 between the applications software 8 and the modem port 2 for communicating the applications software 8 through the modem port 2 with the modem 4.

A diverter according to the invention which is indicated generally by the reference numeral 12 comprises two parts, namely, an identifying and diverting part 14 and an ISDN driver 15, both of which are implemented in software. The identifying and diverting part 14 sits on top of the COMM driver 10 between the applications software 8 and the COMM driver 10 for selecting one of the modem port 2 and the ISDN port 6, in response to an identifying signal, namely, a port select command from the applications software 8. The applications software 8 is suitable for communicating through the modem 4 and accordingly, outputs commands in modem format. The identifying and diverting part 14 of the diverter 12 is transparent to the applications software 8 and the COMM driver 10, so that in the event that the applications software 8 is to communicate through the modem 4 all commands and data from the applications software 8 pass through the diverter 12 and onto the COMM driver 10. Additionally, the diverter 12 is operable in the computer 1 simultaneously with the applications software 8 for communicating the applications software 8 with the ISDN port 6 for communication with the ISDN 7. In this way, full advantage may be taken of the speed at which data may be transmitted over the ISDN 7, and there is no delay in communicating the applications software 8 with the ISDN 7 through the ISDN port 6. The ISDN driver 15 is located adjacent the ISDN port 6. Although needless to say, it will be appreciated that the two parts, namely, the identifying and diverting part 14 and the ISDN driver 15 may be located together on top of the COMM driver 10.

The diverter 12 will now be described in detail with reference to the flow charts of Figs. 2 and 3. The flowchart of Fig. 2 illustrates the operation of the identifying and diverting part 14 of the diverter 12, while the flowchart of Fig. 3 illustrates the operation of the ISDN driver 15 of the diverter 12. In this embodiment of the invention the applications software 8 as discussed above issues commands and sends data in modem format. When the applications software 8 wishes to communicate over a PSTN or an ISDN the applications software 8 issues an OPENCOMM command which includes a character or characters which identify the port 2 or 6 through which the data is to be transmitted.

Referring now in particular to Fig. 2 the identifying and diverting part 14 of the diverter 12 comprises a block 20 which starts operation of the diverter 12. On calling up of the applications software 8 in the computer 1, block 20 is activated for activating the diverter 12. On block 20 having been activated, the software of the diverter 12 moves to block 21 which waits for and reads commands from the applications software 8. On block 21 having read a command, the software moves to block 22 which checks if the read command is an OPENCOMM command. In other words, a command for opening communication to one of the PSTN 5 and the ISDN 7. If the command is not an OPENCOMM command, the software returns to block 21. Should block 22 determine that the command read in block 21 is an OPENCOMM command, the software moves to block 25 which checks if the character included in the OPENCOMM command has identified the modem port 2. If so, the software moves to block 26 which allows communication directly through the diverter 12 between the applications software 8 and the modem port 2, through the COMM driver 10. The software then moves between block 26 and a block 27 which checks for a CLOSECOMM command from the applications software. A CLOSECOMM command is a command for terminating a call. On block 27 determining that a CLOSECOMM command has been read by the identifying and diverting part 14 of the software, the software returns to block 21.

Should block 25 determine that the character included in the OPENCOMM command does not identify the modem port 2, the software moves to block 30 which checks if the character in the OPENCOMM command has identified the ISDN port 6. If not, the software returns to block u 9604()3 21. Should block 30 determine that the character included in the OPENCOMM command has identified the ISDN port 6, the software moves to block 33. Block 33 calls up the ISDN driver 15 of the diverter 12. The operation of the ISDN driver software will be described below with reference to Fig. 3. The software then moves to block 34 which waits for an identifier from the ISDN driver software, and then moves to block 35. Block 35 reads the identifier and stores it, and writes the identifier to the applications software 8, so that all subsequent commands and data to be sent to the ISDN port 6 contain the identifier. Typically, the identifier is a single digit number. The software moves to block 38 which allows direct communication between the applications software 8 and the ISDN driver 15 through the identifying and diverting part 14 of the diverter 12. The applications software 8 sends data to the ISDN driver 15 via a WRITECOMM command. The identifying and diverting part 14 of the diverter 12 then cycles between block 38 and the block 39 which checks if a CLOSECOMM command has been sent by the applications software 8. On block 39 determining that a CLOSECOMM command has been sent by the applications software 8 the software of the identifying and diverting part 14 is returned to block 21.

Referring now to Fig. 3 the operation of the ISDN 96003driver 15 will now be described. Block 50 of the ISDN driver 15 starts the driver software in response to block 33 of the identifying and diverting part 14 of the software. On being activated the ISDN driver software moves to block 51 which initialises memory locations in the ISDN driver 15, and moves to block 52, which generates and writes the identifier to the software of the identifying and diverting part 14 of the diverter 12 which is read by block 35 for subsequent writing to the applications software 8 as already described.

On writing the identifier to the identifying and diverting part 14 of the diverter 12 the ISDN driver software moves to block 54 which waits for a command or a data stream from block 38 of the identifying and diverting part 14. The ISDN driver software then moves to block 55 which reads the command or data stream received from block 38 of the identifying and diverting part 14. The ISDN driver 15 then moves to block 56 which checks if the command or data stream is accompanied by the identifier. If not, the software is returned to block 54. On block 56 determining that the command or data stream comprises the identifier, the software moves to block 57 which checks if it was a command that was read by block 55. If not, the software moves to block 58 which checks if it was a 1960463 data stream that was read by block 55, and if not, the software returns to block 54. On block 58 determining that it was a data stream that was read by block 55 the software moves to block 60 which will be described below.

On block 57 determining that a command was read by block 55, the software moves to block 62. Block 62 checks if the command received from the applications software 8 was a modem command ATD instructing that a B-channel be established on a line of the ISDN 7. If so, the software moves to block 63 which calls up a standard sub-routine for establishing one of the B-channels of the ISDN line. The software then moves to block 64 which waits for confirmation from the subroutine of block 63 that a B-channel has been established. The software then moves to block 65 which checks if a B-channel has been established, and if not, the software is returned to block 63. On block 65 determining that a B-channel has been established the software moves to block 66 which, if a second B-channel is to be established on the line of the ISDN 7, checks if the second B-channel has been established. In this embodiment of the invention, since an ISDN line comprises two B-channels, in order to avail of the two B-channels for speeding up the transfer of data from the computer 1 to another computer over the ISDN 7, a facility is provided for enabling the user to select either one or both of the two B-channels for sending data. If a second B-channel is to be established, and block 66 determines that the second B-channel has not been established, the software returns to block 63. On block 66 determining that the second B-channel has been established, the software moves to block 68 which confirms that the two B-channels have been established to block 36 of the identifying and diverting part 14 of the diverter 12, and the ISDN driver software is returned to block 54. Should the ISDN driver software be instructed to establish only one B-channel, on the B-channel having been established, block 66 moves the software to block 68 which returns the software to block 54. The operation of the software from block 54 after the B-channel or B-channels, as the case may be, have been established will be described below.

However, before describing this part of the ISDN driver software in detail, the remainder of the software from block 62 will now be described.

Should block 62 determine that the command from the applications software 8 is not an ATD modem command, the software moves to block 70. Block 70 checks if the command from the applications software 8 is an ATH modem command, namely, a command that the ISDN telephone line is to be terminated, and if block 70 ^960463 determines that the command is an ATH command the software moves to block 71 which calls up a standard hang-up sub-routine terminating the ISDN line, and control is returned to the identifying and diverting software. Should block 70 determine that the command is not an ATH command, the software moves to block 72 which checks if the command is an ATZ modem command, namely, a reset command. If so, the software moves to block 73 which resets the driver software, and returning control to the identifying and diverting software. Should block 72 determine that the command is not an ATZ command the software moves to block 74 which checks if the command is an ATS0=l modem command.

If so, the software moves to block 75 which instructs the ISDN driver software to answer any subsequent incoming ISDN calls through the ISDN port 10 which are directed by the ISDN driver 15 through the identifying and diverting part 14 to the applications software 8, and control is returned to the identifying and diverting software. Should block 74 determine that the command is not an ATS0=l command, the ISDN driver software moves to block 76 which returns the ISDN driver software to block 50 and returns control to the identifying and diverting software.

Returning now to the operation of the ISDN driver software after block 68 returns the software to block k-960463 54, once the one or two B-channels have been established the applications software 8 sends a data stream using a WRITECOMM command for transmission on the ISDN 7 for which block 54 waits. The software then as already described moves to block 55 and on determining that a data stream has been received by block 54, block 55 reads the data, and the software moves to block 56 which checks if the identifier accompanies the data stream. If so, which will most likely be the case, the software moves to block 57 which on determining that the data stream is not a command moves the software to block 58. On block 58 determining that a data stream has been read by block 54, the software moves to block 60. Block 60 checks the speed at which the data is to be transferred. If the data is to be transferred at 128 bits per second, two B-channels will have been established by the subroutine of block 63. On the other hand, if the data is not to be transferred at a speed of 128 bits per second, the data will be transferred at 64 bits per second on a single B-channel.

On block 60 determining that the data is not to be transferred at 128 bits per second, the software moves to block 80. Block 80 forms the data into data packets, and moves to block 81, which sends the data in the data packets sequentially on the B-channel . 960463 established on the line of the ISDN 7. Block 81 returns the software to block 54 to await further data for transmission as already described.

Should block 60 determine that the data is to be transferred at 128 bits per second, the software moves to block 85 which forms the data into data packets and sequentially numbers the data packets. The software moves to block 86 which sends the data packets sequentially on the two B-channels on the line of the ISDN 7. The data packets are sent on the B-channels in such a way that approximately half the data packets are sent on one B-channel and the other half of the data packets are sent on the other B-channel. Typically, alternate data packets are sent on the respective Bchannels. For example, all data packets with even numbers are sent on one B-channel and all data packets with uneven numbers are sent on the other B-channel.

The sequential numbering of the data packets enables them to be reassembled in the correct order by the computer receiving the data packets. The software then returns to block 54 to await the next data stream.

Returning to block 75, once the ISDN port 6 has been activated to receive incoming calls on the ISDN network 7, a sub-routine of the ISDN driver is called up. The operation of the sub-routine for receiving calls and 96046 J communicating the calls with the applications software 8 is essentially the reverse of the software of the ISDN driver 15 which has just been described with reference to Fig. 3. Incoming commands in ISDN format are converted to commands in modem format and relayed to the applications software 8 through the identifying and diverting part 14 of the diverter 12. Such an arrangement of software will be readily apparent to those skilled in the art.

Additionally, the sub-routine of the ISDN driver 12 for answering and receiving calls comprises an algorithm for receiving data in data packets on two B-channels of an ISDN line, in other words, for receiving data at the rate of 128 bits per second which avoids slowing down of the data transmission in the event of minor corruption of the data. Briefly, the algorithm receives the numbered data packets, and arranges them sequentially. Should it be determined that a data packet is missing, the sub-routine waits for a predetermined period of time, which in this case, is five seconds. On the missing data packet of data being received the receive sub-routine continues to assemble the data packets sequentially in numbered order. On the missing data packet not appearing within the five second predetermined period the receive sub-routine looks for the next data packet numbered sequentially upwards from the B-channel from which the data packet is missing. If a higher numbered data packet is found, but the higher numbered data packet is not the next sequentially numbered data packet, the receive subroutine waits for a further three seconds for the missing said next sequentially numbered data packet to appear. If after three seconds the missing said next sequentially numbered data packet has not appeared, the receive sub-routine then takes the said next higher numbered data packet, and the software then commences to synchronise the data packets in number order being received on the two B-channels.

The advantages of the invention are many. Firstly, by virtue of the fact that the diverter 12 is mounted on top of the COMM driver 10 and is transparent, the applications software 8 can communicate directly through the modem 2 without any delay. Furthermore, by virtue of the fact that the software of the diverter 12 can operate simultaneously with the applications software 8 there is no delay in communicating the applications software 8 with the ISDN port 6, and in turn, the ISDN 7, and full advantage of the rapid rate at which data can be transferred on ISDN, either at 64 bits per second or at 128 bits per second can be fully utilised. 96046} It will of course be appreciated that the diverter according to the invention may be used for communicating over the Internet, and for Internet working at 64K, the diverter would be provided with point to point protocol according to RFC1618.

While the ISDN port of the computer has been described as being CAPI compliant, it will be appreciated that the ISDN port may be compliant to other standards.

Claims

1. A diverter for locating in a computer for selecting one of a modem port and an ISDN port of the computer in response to applications software resident in the computer, the applications software being of the type for communicating the computer through the modem port for permitting communication with a PSTN through a modem, and the computer being of the type comprising a COMM driver for communicating the applications software with the modem port, the diverter being locatable in the computer between the applications software and the COMM driver, and being transparent to the applications software, and the diverter comprising a means for allowing commands and data to pass therethrough uninterrupted to the COMM driver where data is to be sent by the applications software through the modem port, a means for diverting commands and data to be sent to the ISDN port, an ISDN interface means for interfacing the applications software with an ISDN, and for sending data over the ISDN, and a conversion means for converting commands in modem format to the equivalent commands associated with ISDN, the diverter being operable simultaneously with the applications software for communicating the applications software with the ISDN.

2. A diverter as claimed in Claim 1 in which the 96 046 3 means for allowing the commands and data to pass through the diverter to the COMM driver and for diverting commands and data to the ISDN port are responsive to signals identifying the ISDN port and the modem port, respectively, received from the applications software.

3. A diverter as claimed in Claim 1 or 2 in which the means for allowing commands and data to pass through the diverter to the COMM driver and for diverting commands and data to the ISDN port comprise a reading means for reading commands from the application software, and for reading the identity of the port specified by the applications software through which the commands and data are to be sent.

4. A diverter as claimed in Claim 3 in which the reading means comprises a means for reading an OPENCOMM command from a Windows operating system for opening communications with the PSTN or the ISDN. 5. A diverter as claimed in Claim 3 or 4 in which the reading means comprises a means for reading a CLOSECOMM command for returning the diverter to a waiting mode for awaiting the next OPENCOMM command. 6. A diverter as claimed in any preceding claim in 96046} which the ISDN interface means comprises an ISDN driver. 7. A diverter as claimed in claim 6 in which the ISDN driver comprises a means for initialising memory 5 locations, and a means for setting up a channel in the ISDN in response to an ATD command from the applications software. 8. A diverter as claimed in Claim 7 in which the means for setting up a channel in the ISDN sets up one 10 B-channel on a line in the ISDN. 9. A diverter as claimed in Claim 7 or 8 in which the means for setting up a channel in the ISDN sets up two B-channels on a line in the ISDN. 10. A diverter as claimed in any preceding claim in 15 which the diverter comprises a means for packing data to be sent on the ISDN into data packets. 11. A diverter as claimed in Claim 10 in which the data packets are sequentially numbered and where two Bchannels are set up, substantially half the data 20 packets are sent on one B-channel and the other half of the data packets are sent on the other B-channel. 960463a 12. A diverter as claimed in any preceding claim in which the diverter comprises an identifying and diverting part for identifying commands and data from the applications software and for diverting commands and data to the ISDN port, and an ISDN driver for driving the ISDN port, the identifying and diverting part of the diverter being adapted to sit just above the COMM driver between the applications software and the COMM driver, and the ISDN driver being adapted to sit above the ISDN port between the identifying and diverting part and the ISDN port. 13. A diverter as claimed in any preceding claim in which the diverter is suitable for use in a computer in which the ISDN port is CAPI compliant and supports versions 1.1 or 2.0. 14. A diverter for locating in a computer for selecting one of a modem port and an ISDN port of the computer in response to applications software resident in the computer, the diverter being substantially as described herein with reference to and as illustrated in the accompanying drawings. 15. A computer comprising the diverter as claimed in any preceding claim wherein the diverter is located in the computer between the applications software and the 9β04«3 COMM driver. 16. A computer as claimed in Claim 15 in which the identifying and diverting part of the diverter is located to sit just above the COMM driver, and the ISDN driver is located to sit above the ISDN port. 17. A computer as claimed in Claim 15 or 16 in which the applications software and the diverter are operable simultaneously in the computer. 18. A computer substantially as described herein with reference to and is illustrated in the accompanying drawings . 19. A method for operating a computer under the control of applications software and the diverter as claimed in any of Claims 1 to 14 wherein the diverter, on receiving a command from the applications software identifying one of a modem port and an ISDN port, selects the appropriate port and communicates the applications software with the selected port. 20. A method as claimed in Claim 19 in which the diverter converts a command in modem format received from the applications software into ISDN format for sending over the ISDN. 21. A method as claimed in Claims 19 or 20 in which commands and data from the applications software to be sent to the modem port are allowed to pass through the diverter directly to the COMM driver.

5. 22. A method for operating a computer, the method being substantially as described herein with reference to and as illustrated in the accompanying drawings.