DC3021 G.703/X.21 Converter
- Speed - 2.048mb/s
- Interface - 75ohm BNC to 120ohm RJ45
- PCM input sensitivity to -43dB
- Line status and BPV indication
The DC3021 is a basic PCM converter unit which provides a conversion from either a BNC or RJ45 interfaced network to a standard X.21 interface presented on a 15 way ‘D’ type socket. It is simple to fit and there are no internal options to set as the unit is designed to only function with a PTT supplied network, which will provide the timing.
The front panel Line indicator allow the user to identify that valid HDB3 data is being received. If Green, valid HDB3 signal are detected otherwise the LED is red. If errors are detected in the HDB3 encoding of the data, creating a bipolar violation, the Line indicator will flash Yellow for each violation.
As the X21 interface only accommodates a single clock signal, used for both transmit and receive data, it is important that all data is referenced to a single source. Normally this source is derived from the PCM network so equipment at each end of the link must be set to slave timing. Remote Loopback Facility
The product permits a network loop to be applied remotely via the PCM interface. This allows a user to check that the circuit is functioning correctly. The DC3021 is primarily designed to be used in conjunction with the ET2148 tester which can both apply and remove loops as well generate and check test pattern data. This handheld device can display both bit errors and also count Bi-Polar Violations that may be occurring.
When a loopback is initiated, the incoming network signals are cleaned, regenerated and sent out again. The equipment X21 interface can be set either to monitor the incoming diagnostic information or ignore it. No equipment interface loopback option is available with this unit and no switches are provided to locally apply loops which helps prevents operational problems due to unauthorised actions.
When the loopback is activated, the Loop indicator will flash Yellow until the loop is removed.
Testing G.703 circuits
- ET2148 G.703 Tester:The ET2148 is a sophisticated handheld tester capable of identifying a wide variety of circuit conditions, yet is extremely easy to use.
- ET2021 X.21 Tester:The ET2021 is a part of the range of pocket size testers specifically designed aiding the installation, commissioning and fault finding on X.21 high speed circuits (up to 2Mb/s) and includes an integral BERT (Bit Error Rate Tester).
DC3021 Specification
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