Digital subscriber line user isolation device loop device
Technical field
The utility model belongs in the telecommunication system, and the public data communication net detects and service equipment subscriber's line, relates to DDN, PSPDN etc. and utilizes the subscriber's line of two cable copper wire accesses at it, constitutes the device of loop at the user side short circuit.
Background technology
Current data communication has been one of indispensable main communication mode of information-intensive society.Along with the continuous growth of data communication service, the professional private networks of various public data communications (PSPDN, DDN, DCN etc.) constantly enlarge, and communication capacity, transmission rate improve constantly.At present, insert under the condition that adopts the cable copper cash the user, the data communication rates that subscribers feeder (cable copper twisted pairs) can transmit Baseband Modem has reached 64Kb/s, even it is higher, newly emerge in large numbers data communication service existing N-ISDN, HDSL, ADSL, reach XDSL etc., the DATA and the AV business of 2048Kb/s speed is provided.Therefore, how to utilize the existing existing huge resource of copper cable Access Network to expand transmission broadband new business, nature just becomes the problem that telecommunications operator and telecommunication technology research department are paid close attention to.
Being based upon N-ISDN, DDN on the service cable copper wire access basis, ADSL etc. in recent years receives praises from customers, be used widely in all departments such as finance, education, scientific research, enterprise, security, develop very fast (for example the present Jiangsu of DDN user reaches more than 60,000), growth trend is good., seeming incompatible at present is the digital subscriber line failure rate height that adopts cable copper cash mode, and its reason mainly is to lack corresponding maintenance test means and supporting maintenance test equipment, can not pinpoint the problems immediately, fixes a breakdown rapidly.Such as, subscriber's line picks out from the MDF (main frame) of local side in the DDN system, is connected to user Modem by a pair of cable copper cash, sees shown in Figure 1.Statistics showed in the past, because the caused failure rate of subscriber's line fault accounts for more than 70% of whole system failure rate, therefore most important to the maintenance of subscriber's line, and judge that the parameter of link performance quality has a lot, wherein, the loop resitance of subscriber's line is one of most important parameter.Method that loop resitance adopted and the step of measuring subscriber's line at present are:
1, at user side subscribers feeder is pulled up from Modem, two line short circuits.
2, measure the loop resitance of these two circuits at local side.
Above processing mode shortcoming is:
1, complex operation need access this subscriber data earlier during processing, from the thousands of of distributing frame a pair of line of finding out this user the line is handled then.
2, need each department's co-operation, will obtain user's compounding practice especially, can cause that usually the user dislikes.
3, because the subscribers feeder of user side generally inserts Modem by RJ45 connector, so the end of a thread can not expose outside, can't carry out short circuit.If, RJ45 connector need be cut with its short circuit, expose the end of a thread, could short circuit.With special-purpose conductor clamp line is connected a new crystal head again after surveying well.But most users do not possess these instruments, thus often need the special messenger of telecom operators to go up door operation, and also every survey once will be wasted a crystal head.
4, because its complex operation may not done in daily routine maintenance like this, can only break down the user and adopt when the back is tested specially to this user.
At above problem, the utility model purpose provides a kind of loop device of realizing short circuit at user side.This device is accepted control centre's instruction and finish the short circuit task between a pair of subscribers feeder of user side, carries out the measurement of loop resitance to cooperate testing equipment.
Summary of the invention
For achieving the above object, the technical solution adopted in the utility model is: a kind of digital subscriber line user isolation device loop device is characterized in that comprising:
Double-tone is decoding circuit frequently, and input is connected with subscribers feeder, receives the double-tone frequency switching signal of local side, and output produces corresponding decoded signal;
The CPU processor receives the decoded signal that double-tone frequency decoding circuit is exported, and sends corresponding switch-over control signal;
Drive circuit, the switch-over control signal that input response CPU processor sends, output produces the corresponding driving signal;
Commutation circuit, constitute by relay, relay has one group of contact to connect the path of subscribers feeder IN1, subscribers feeder IN2 and subscribers feeder OUT1, subscribers feeder OUT2, relay has another group contact to connect the short circuit loop of subscribers feeder IN1 and subscribers feeder IN2, and the control end of relay links to each other with the respective drive signal of drive circuit output.
The related content of technique scheme is explained as follows:
1, in the such scheme, if the user side circuit only is provided with conducting and two kinds of operating states of loop, so in order to simplify commutation circuit, adopt the relay of a band double-point double-throw switch just passable, wherein, a single-pole double throw diverter switch is used for connecting the path of subscribers feeder IN1, subscribers feeder IN2 and subscribers feeder OUT1, subscribers feeder OUT2, and another single-pole double throw diverter switch is used for connecting the short circuit loop of subscribers feeder IN1 and subscribers feeder IN2.If the user side circuit except being provided with conducting and loop, also be equipped with the operating state that other need switch by relay, such as, open circuit, quiet terminal etc., should adopt each functional separation each relay to control separately this moment.It is specific as follows to simplify commutation circuit:
Commutation circuit contains the relay of two band dpdt double-pole double-throw (DPDT) diverter switches, first relay K 3 is located in subscribers feeder and the circuit that user Modem is connected, wherein, three terminals of a single-pole double throw diverter switch are connected with the end that suspends subscribers feeder IN1, subscribers feeder OUT1, and three terminal respective user line IN2, subscribers feeder OUT2 of another single-pole double throw diverter switch are connected with the end that suspends; Second relay K 5 is located in subscribers feeder and the circuit that loop is connected, wherein, three terminal respective user line IN1 of a single-pole double throw diverter switch, the end that suspends are connected with loop end A, and three terminal respective user line IN2 of another single-pole double throw diverter switch, the end that suspends are connected with loop end B; The respective drive signal of the control end of two relay K 3, K5 and drive circuit output links to each other.
2, in the such scheme, in order to prevent that double-tone frequency decoding circuit from exerting an influence to the signal on the subscribers feeder, subscribers feeder IN1 is connected with double-tone frequency decoding circuit input through buffer circuit with subscribers feeder IN2, buffer circuit is made of capacitor C 11, capacitor C 12 and transformer T1, subscribers feeder IN1 and subscribers feeder IN2 connect the elementary winding of transformer T1 respectively after capacitor C 11 and capacitor C 12, secondary winding connects the double-tone input of decoding circuit frequently.
3, in the such scheme, double-tone decoding circuit frequently can adopt 8870 double-tones decoding chip or 9370 double-tones frequency decoding chip or other double-tone frequency decoding chip frequently.
The utility model operation principle:
One, former DDN data communication system
Shown in accompanying drawing 1, local side is made up of node machine (communication apparatus), Modem and MDF (main frame).User side is made up of Modem and data equipment.Every pair of subscribers feeder is made up of two cable copper cash.
Two, cooperate the system that realizes the subscribers feeder loop resistance measurement
In order to make the utility model realize the loop task, need following test macro and cooperate at local side:
Test macro comprises: test center, testing equipment, wherein:
Test center is a software section, and being installed in the computer of data center of telecom operators becomes a control centre;
Testing equipment is installed in the machine room of local side, is serially connected on the MDF.
Three, MDF (main frame) mode of connection in the former DDN system
Shown in accompanying drawing 2, line 1 leads to the Modem of local side, and line 2 leads to subscribers feeder.Be connected by MDF at DDN system center line 1 and line 2.
Four, test macro access way
Shown in accompanying drawing 3, testing equipment is connected in series into and among the MDF is: line 1 and line 2 are disconnected, and line 1 connects the inlet wire of testing equipment, and line 2 connects the outlet of testing equipment.
Five, subscribers feeder loop principle
Referring to accompanying drawing 4 and shown in Figure 5, the isolator loop device is installed in user side, and serial connection inserts between subscribers feeder and the Modem, under its normal operating conditions, the isolator loop device is by the double-tone signal that transmits on the listening-in line constantly of decoding circuit frequently, but do not influence user's work.When needs test subscriber line loop resistance, test macro sends the double-audio signal order from test center's order testing equipment from subscribers feeder, double-tone decoding circuit is frequently given CPU with signal after receiving order, CPU judges instruction, if confirmation command is the loop instruction, CPU sends switch-over control signal by drive circuit, make relay K 3, the K5 action, wherein, relay K 3 subscribers feeders and Modem disconnect, relay K 5 makes local side carry out the test of loop resitance the subscribers feeder short circuit, keep subscribers feeder short circuit state after a period of time CPU reuse the family line and return to normal communication state.
Because the technique scheme utilization, the utility model compared with prior art has following advantage:
1, simple to operate, so long as insert the subscribers feeder of test macro, only need on the computer of test center, choose this user's name, can carry out the test of loop resitance.
2, can carry out the detection of loop resitance at any time.
Description of drawings
Accompanying drawing 1 is the DDN block diagram of system.
Accompanying drawing 2 is MDF in the DDN system (main frame) wiring schematic diagram.
Accompanying drawing 3 inserts schematic diagram for testing equipment.
Accompanying drawing 4 is the user side winding diagram.
Accompanying drawing 5 is the utility model theory diagram.
Accompanying drawing 6 is the utility model embodiment commutation circuit and double-tone frequency decoding circuit figure.
Embodiment
Below in conjunction with drawings and Examples the utility model is further described:
Embodiment: referring to accompanying drawing 5 and shown in Figure 6, a kind of digital subscriber line user isolation device loop device is by double-tone frequency decoding circuit, CPU processor, drive circuit and commutation circuit.IN1, IN2 are stimulus part, are connected with subscribers feeder; OUT1, OUT2 are segment signal output, are connected with user Modem.
Double-tone decoding circuit frequently is made up of 8870 double-tones frequency decoding chip U5, resistance R 25, capacitor C 13, resistance R 26, resistance R 27, crystal oscillator Y2, capacitor C 16, resistance R 28, input is connected with subscribers feeder IN1, IN2 by buffer circuit, buffer circuit is made of capacitor C 11, capacitor C 12 and transformer T1, subscribers feeder IN1 and subscribers feeder IN2 connect the elementary winding of transformer T1 respectively after capacitor C 11 and capacitor C 12, secondary winding connects the double-tone input of decoding circuit frequently.Buffer circuit plays buffer action, prevents from signal on the subscribers feeder is exerted an influence.Double-tone frequency decoding circuit is used to receive the double-tone frequency switching signal of local side, and output DTMF1~DTMF4 produces corresponding decoded signal.
The CPU processor receives the decoded signal that double-tone frequency decoding circuit is exported, and sends corresponding switch-over control signal.
Drive circuit, the switch-over control signal that input response CPU processor sends, output produces the corresponding driving signal.
Commutation circuit is made up of the relay of two band dpdt double-pole double-throw (DPDT) diverter switches, first relay K 3 is located in subscribers feeder and the circuit that user Modem is connected, wherein, three terminals of a single-pole double throw diverter switch are connected with the end that suspends subscribers feeder IN1, subscribers feeder OUT1, and three terminal respective user line IN2, subscribers feeder OUT2 of another single-pole double throw diverter switch are connected with the end that suspends; Second relay K 5 is located in subscribers feeder and the circuit that loop is connected, wherein, three terminal respective user line IN1 of a single-pole double throw diverter switch, the end that suspends are connected with loop end A, and three terminal respective user line IN2 of another single-pole double throw diverter switch, the end that suspends are connected with loop end B; The respective drive signal of control end RL13, the RL15 of two relay K 3, K5 and drive circuit output links to each other.
In normal operation, two relay K 3, the control end RL13 of K5, RL15 is a high level, relay K 3, K5 must not, subscribers feeder IN1, IN2 and subscribers feeder OUT1, OUT2 is communicated with, the proper communication of user's energy, in the time of need carrying out loop to subscribers feeder, office testing device sends the instruction of double-audio signal on subscribers feeder, the double-tone of isolator decoding circuit is frequently delivered to CPU with double-audio signal decoding output, CPU judges instruction, if instruction is correct, be the loop instruction, CPU is by the control end RL13 of drive circuit with relay, RL15 becomes low level, relay K 3, the K5 action, with subscribers feeder IN1, IN2 and subscribers feeder OUT1, OUT2 disconnects, with subscribers feeder IN1, IN2 makes subscribers feeder constitute loop by relay K 5 short circuits.
At this moment, the testing equipment of local side gets final product the loop resitance of test subscriber's line.The CPU of isolator is after keeping subscribers feeder short circuit state a period of time (being set at 30 seconds), and the control end RL13, the RL15 that put relay again are high level, makes subscribers feeder recover normal communication state.