1.5 Administrator's Guide

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  4. Commissioning the unit
  5. Configuring Comma device ports
  6. Configuring PRI

Configuring PRI



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) The physical interface configuration must match that of the PRI peer.

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

Signaling role

When configured as Terminal, the device is an ISDN TE, connected to the telco NT. When configured as 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 dialing

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 being established before the remaining digits arrive.