E1/T1 Trunk Introduction
E1/T1 is known as Primary Rate Interface (PRI), is an Integrated Services Digital Network (ISDN) access method, which enables traditional phone lines to carry voice, data and video traffic, among others.
Note: Yeastar S100 and S300 supports PRI E1/T1/J1 trunk. To extend E1/T1/J1 trunk, you
need to install EX30 expansion board on S100/S300. One EX30 expansion board provides
1 E1/T1/J1 port.
The PRI consists of B channels at 64 kbit/s each and D channel at 64 kbit/s each. The B channels are used for voice or user data, and the D channel is used for any combination of data, control/signalling, and X.25 packet networking.
According to the number of B-channels and D-channels, there are three types of PRI interface: E1, T1 and J1.
| PRIs Type | Description |
|---|---|
| E1 |
Contains 30 B-channels and one D-channel and used in Europe, China and most of the Asia countries. |
| T1 | Contains 23 B-channels and one D-channel and used in the USA, Canada and Hong Kong. |
| J1 | It is almost the same as T1 but used in Japan with some slight modifications, this is the Japanese standard for PRI. |