PCM equipment and PDH optical transceiver cascade guidance

PCM devices carry various service data through 2M channel, and PDH optical transceiver transmit standard 2M data through optical fiber. At present, the use of PDH optical transceiver and PCM device is one of the most common networking solutions, but many users will encounter such a problem, "How is the PCM device connected to the PDH optical transceiver?". The following brief description of the cascading operation method of PCM equipment and PDH optical transceiver

1. PDH optical transceiver link wiring

As an optical transmission device, ZMUX-100 converts electrical signals (PCM device signals) into optical signals for transmission on optical fibers. As a bridge between the two sites, in general, we first turn the ZMUX-100 link to make the ZMUX-100 in normal operation, and then cascade the ZMUX-30 application.

The ZMUX-100 comes standard with dual-fiber transmission. It has two optical interfaces (left side transmit and right side receive). The receiving interface of the central station should correspond to the transmitting interface of the remote station. The transmitting interface of the central station should correspond to the receiving interface of the remote station. Only when the receiving and transmitting interfaces are connected, the ZMUX-100 can work normally (as shown below). If the PWR indicator of the device is on and the other alarm lights are off, the connection is normal. (Reference: PDH optical transceiver installation and debugging instructions)

2. PCM equipment cascade PDH optical transceiver

When the ZMUX-100 is working properly, we can perform the ZMUX-30 cascading ZMUX-100 step. The 2M interface of ZMUX-100 adopts DB37-CC4B-8/DB37-CC4B-16 converter. The up and down CC4 connectors are a group of 2M, the up is the transmitting, the bottom is the receiving (as shown in Figure 1), ZMUX-30 2M connector is left（transmitting)and right(receiving). At this time, we only need to connect the 2M connector of ZMUX-100 and ZMUX-30 with one twin-core coaxial cable (as shown in Figure 2).

If the ZMUX-30 PWR light is on and the other warning lights are off, the connection is normal (refer to the PCM device installation and commissioning instruction manual). When engineering, remember that the DB37-CC4B converter is up(sending) and down(receiving), and the up and down CC4 connectors are a set of 2M connectors, which can be wired as shown in the figure above.