Implementing Trunk Termination
While not required, most PBX systems are connected to at least one T-1 circuit
for connectivity to either the PSTN or another PBX within the company.A
trunk is a T-1 or other type of circuit, which can carry multiple channels, or time
division multiplexed (TDM) data streams. Recall that these connections can carry
up to 24 voice connections depending on their framing and signaling. Please note
that trunks can also use the E-1 standard, which allows for 30 user channels.
NOTE
Some trunks are called tie lines, which are simply trunks used for connections
to another PBX. In some instances these connections are only
capable of carrying voice channels; additional functions are provided in
others. One example is Siemens’ CorNet, which can provide most intra-
PBX services between inter-PBX devices.