PRI Card

Trunk cards can be fitted to existing base cards to provide support for trunk ports. The trunk card uses the ports provided on the base card for cable connection. Each trunk card comes with spacer pegs for installation and port identification labels.


These cards are used for PSTN/FXS gateways with IP Office for Linux.


In systems with both Analog Phone 8 base cards and analog trunk cards, combining the two types are recommended because it provides analog power failure support for one trunk per extension (not applicable to the Analog Phone 2 base card).

Table 1: IP500 V2 trunk cards

Trunk card

Maximum per system


Analog (V2)


4 analog loop start trunks

V.32 modem for remote access

1 power failure extension to trunk connection on Phone 8 cards

Not supported with VCM cards.

Universal PRI (PRI-U)


Up to 2 PRI trunk connections. The card is available in single and dual port variants. The card can be configured for E1 PRI, T1 robbed bit, T1 PRI or E1R2 PRI trunks.

Supports primary rate digital trunks.

On each card, 8 channels per interface are enabled by default. This means that the single PRI has 8 channels enabled, while the dual PRI has 8 channels enabled on each of the two circuits. Further channels may be enabled by the purchase of additional licenses in 2-channel or 8-channel increments.

Available in single and dual version. The single variant can support up to 24 T1 channels or up to 30 E1 channels. The dual variant can support up to 48 T1 channels or 60 E1 channels.

Configurable for T1, E1, E1R2 MFC use, depending on territory.

Includes an integrated CSU/DSU:

  • CSU allows trunks to be put into loop-back mode for testing purposes. This can be set manually, using the monitor application, or automatically from a Central Office sending a Line Loop Back (LLB) pattern.

  • DSU allows the T1 trunk to be shared between data and voice services.

Includes diagnostics capabilities: visual indicators to show service state and physical test points to monitor traffic.



Up to 4 BRI trunk connections, each trunk providing 2B+D digital channels.

Available in 2 (4 channels) and 4 (8 channels) options.

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