A single E1 link carries only 2.048Mbps, so how can it transmit telephone and serial port data at the same time?
The IDM MINI8 uses the PCM30/32 frame structure to divide the 2.048Mbps E1 channel into 32 time slots (TS): 30 of these time slots carry 64 kbit/s services, and the remaining time slots are used for f
The IDM MINI8 uses the PCM30/32 frame structure to divide the 2.048Mbps E1 channel into 32 time slots (TS): 30 of these time slots carry 64 kbit/s services, and the remaining time slots are used for frame alignment and channel-associated signaling (CAS). Voice services are first encoded into 64Kbps digital signals using A-law in ITU-T G.711 and then occupy one 64K time slot; RS232/RS422/RS485 serial port data runs at a lower rate and can be multiplexed onto low-speed time slots in the same E1. The various service types are independent of one another in the time slots, so telephone and serial port data can be transmitted in parallel, and a change in one service does not affect the other services. The 2.048Mbps bit rate and HDB3 line coding of the E1 interface comply with ITU-T Recommendation G.703.