Please Help Me Check whether the Cable Connect is Correct because the External Clock Synchronization is Faults

1. Checked cable connection at NodeB 1 because it reported an alarm indicating the loss of clock signals from an external clock port.

The external clock port on NodeB 1 was a 75-ohm coaxial port and the external clock port on NE B was a 120-ohm twisted-pair port. To connect the external clock port on NE B to the external clock port on NodeB 1, an impedance converter box (Balun-box) was installed on the external clock port of NE B.

The wire connection diagram of the converter box shows that the Tx wire from NE B was connected to the Rx end of the converter box and the Rx wire from NE B was connected to the Tx end of the converter box. Cable connection examination showed that the Tx wire from the converter box was connected to the Rx end of NodeB 1 and the Rx wire from the converter box was connected to the Tx end of NodeB 1. As a result, the Tx wire from NE B was connected to the Tx end of NodeB 1 and the Rx wire from NE B was connected to the Rx end of NodeB 1, so signals were unavailable.

2. Corrected the cable connection. NodeB 1 could trace clock signals normally.

Conclusions and Suggestions

Cable connection between interworking equipment must meet the following requirements:

• The Tx port at the local end is connected to the Rx port at the opposite end, and the Rx port at the local end is connected to the Tx port at the opposite end.
• If two ports are connected using a twisted pair, the positive end of the local port is connected to the positive end of the opposite port, and the negative end of the local port is connected to the negative end of the opposite port.