E1 is an transmission link ,it is widely used in telecom operators. one of the TAK communciation’s main products is E1 interface converter, such as E1 to Ethernet converter, E1 to serial data converter,E1 to V.35 converter,and so on. The following is the introduction of E1.

1. introduction (1) 1 line E1 is the link of 2.048M , using PCM coding. (2) The frame lenght of 1E1 is 256 bit, divided into 32 time slot, one slot is 8 bit. (3) there are 8k E1 frame go through the interface per second , namely, 8 k * 256 = 2048 kbps.. (4) each time slot in the E1 frame is 8 bit, 8 * 8 k = 64 k, so 1 E1 contains 32 *64 k.

2. E1 frame structure E1 has three kinds: framed , complex frame , unframed, for the framed E1,the 0th time slotis for transmission frame synchronization data, the rest 31 time slots can be used to transmit effective data ; for complex frame E1 ,except the time slot 0, the 16th time slot is used for the transmission signaling, only 1 to 15, 17 to 31, total 30 time slot can be used to transfer effective data ; And for unframed E1, all 32 time slot can be used to transfer effective data.

3. Basic knowledge of E1 frame structure description of E1 channel:In E1 channel, 8 bit form a time slot (TS),32 timeslot form a frame (F), 16 frames form a multiframeframe (MF). In a frame, TS0 is mainly used to transmit frame alignment signa (FAS). CRC - 4(cyclic redundancy check) and remote side alarm instructions, TS16 mainly transmitted the signaling of along with road (CAS), the compound frame positioning signal and remote side alarm instructions, TS1 to TS15 and TS17 to TS31 , total 30 timeslot transmit voice or data information etc.We call TS1 to TS15 and TS17 to TS31 is net load, TS0 and TS16 is for overhead. If USES out-of-band public channel signaling (CCS) , TS16 loses the using purpose of transmitting signal, this time slot is also can be used to transfer information signal, then the net charge of frame structure is TS1 to TS31, only TS0 overhead.

4. E1 interface Have two kinds of interface : G. 703 un-balanced 75 ohm BNC interface, balanced 120ohm RJ45 interface. Each area has its own type of E1 interface,some country use un-balanced 75ohm BNC interface, some country use balanced 120ohm RJ45 interface, it is depends on diffreent customers’s requirements.

Above is the basic introduction of E1. It is pfofessional,but also readable, hope it can help you to know more about E1 and our E1 inerface converter.