3.2.5.4Configuring PRI
Field
Content
Physical interface The service offering, either 23B+D T1 or 30B+D E1. For E1,
double frame or CRC4 multi-frame can be enabled, and for T1
framing can be either Super Frame (D4) or Extended Super
Frame (ESF, using CRC-6)
Switch type
National switch type options are:
•
US National ISDN phase 1 (NI-1)
•
US National ISDN phase 2 (NI-2)
•
ETSI “Euro” ISDN: Europe ISDN standard
•
QSIG: protocol for switching between PBXs
Signalling role
When configured as Terminal, the device is an ISDN TE,
connected to the telco NT. When configured ad Network, this
port acts as though it is an ISDN NT device. This is useful when
the Comma device is placed between the PBX and the telco NT,
e.g. for least-cost routing.
Overlap dialling
Enabling this setting will result in digits being transmitted across
the PRI link as they are dialed, as opposed to the full number
being collected before dialing. Overlap dialing allows a
destination number to be specified partially resulting in the first
stage of a routing path to be established before the remaining
digits arrive.
