The differences among ADM, TM, DXC and REG in SDH equipment are: different circuit services, different functions and different cross connections. According to the definition suggested by ITU-T, SDH international standard is a technical system that provides corresponding information structure for the transmission of digital signals with different rates, including multiplexing method, mapping method and related synchronization method.

First, the circuit business is different.

1, ADM:ADM performs uplink and downlink (add/drop) circuit business, and does not amplify or regenerate optical signals.

2.TM: TM performs uplink and downlink (add/drop) circuit services and does not amplify or regenerate optical signals.

3.DXC:DXC is engaged in uplink and downlink (add/drop) circuit business, and at the same time amplifies or regenerates optical signals.

4.REG:REG does not carry out uplink and downlink (add/drop) circuit business, but only amplifies or regenerates optical signals.

Second, the role is different.

1, ADM:ADM is used to cross-multiplex low-speed branch signals to eastbound or westbound lines; Or separate the low-speed branch signal from the line signal received by the east or west port.

2. TM: The function of TM is to multiplex the low-speed signal of branch port into the high-speed signal STM-N of line port, or to separate the low-speed branch signal from the signal STM-N. ..

3. DXC: The function of DXC is cross connection, which can complete the low-level cross of high-speed signals in the cross matrix.

4. REG: The function of REG is to send optical signals on both sides of w/e through O/E, sampling, judgment, regeneration and shaping, and E or W-side E/O..

Third, the cross-connection is different.

1, ADM:ADM can cross-connect STM-N signals on the east/west side.

2.TM: TM cannot cross-connect STM-N signals on the east/west side.

3.DXC:DXC can cross-connect STM-N signals on the east/west side.

4.REG:REG cannot cross-connect STM-N signals on the east/west side.