Building a T1/E1 Loopback Connector.In order to perform a loopback test of the E1/T1 port, a loopback plug (also known as loopback connector or loopback cable) is needed. An T1/E1 loopback connector can easily be made using a single RJ45 connector and two 4-in (10-cm) wires.
Materials Needed:
- Unused RJ-45 plug
- Two strands of Category 5 (Cat-5) wire, each 4-in (10-cm) long
- Crimp tool for RJ-45
Procedure:
- Insert one end of wire 1 into pin 1 of the RJ45 connector. Note: To ensure a good connection, make sure that each wire goes all the way into the end of the plug.
- Insert the other end of wire 1 into pin 4 of the RJ45 connector.
- Insert one end of wire 2 into pin 2 of the RJ45 connector.
- Insert the other end of wire 2 into pin 5 of the RJ45 connector.
- Crimp the connector.
Now you have a small loopback cable: a single RJ45 connector with pin 1 connected to pin 4,
and pin 2 connected to pin 5.
After you install the loopback cable, check that the span is not in alarm:
For Switchvox systems:
- In the Switchvox Administration go to Diagnostics-->System Status. If the status of that specific span is not "OK", then the T1/E1 loopback cable was made incorrectly (try another loopback cable), or the port is defective.
For Asterisk systems:
- Run the dahdi_tool utility and check if the span reports any alarms or not. If any alarms are reported for the span then the T1/E1 loopback cable was made incorrectly (try another loopback cable), or the port is defective.
