ISDN Voice Interface Cards (VICs) such as VIC-2BRI-S/T-TE connect directly to Public Switched Telephone Networks (PSTNs), Private Branch Exchanges (PBX), and Private Access Branch Exchanges (PABX), supporting both on-premise and off-premise connections.
This table lists the features that are supported on ISDN BRI VICs:
Two ISDN BRI, total of four B channels, therefore four voice calls per VIC.
ISDN BRI S/T RJ-45
VIC-2BRI-S/T-TE—Provides TE ISDN interface. Connects to the telco central office switch or a PBX that provides NT. You cannot connect ISDN phones or faxes to this VIC (it would require NT implementation). VIC-2BRI-NT/TE—Provides TE or NT. VIC2-2BRI-NT/TE—Provides TE or NT. Connects as network side or user side to PBX or key system as off-premises connections (ISDN voice BRI). Supports patent-pending flexible Layer 2 (L2) and Layer 3 (L3) configurations.
ISDN Switch Types
Supports all Cisco IOS® Software ISDN BRI switch types.
The VIC2-2BRI-NT/TE cards are new generation VICs that are a hardware refresh of the older cards of the similar functionality, with resolved manufacture component issues. New functionality is also introduced on these BRI cards (which reduces the number of Stock Keeping Units (SKUs) required).
The VIC2-2BRI-NT/TE is supported on NM-HD-1V, NM-HD-2V, and NM-HD-2VE, where as the VIC-2BRI-S/T-TE and VIC-2BRI-NT/TE are currently supported on NM-1V/2V.
The ISDN parameters are configured similar to a data ISDN BRI interface.
Note: The isdn incoming-voice modem command is required to route the voice call to the digital signal processor (DSP) on the Voice Network Module. For additional information on this command, refer to isdn incoming-voice modem.
Some of the known issues with the BRI VICs are discussed in this section.
When the BRI voice interfaces are configured, this error message is received:
%C542-1-INSUFFICIENT_DSPS: VNM(1), cannot support all voice channels on VICs.
This is because the VIC-2BRI-S/T-TE can have more B channels than the Voice Network Module can handle. The NM-1V can handle two voice calls (has two DSPs). The NM-2V can handle four voice calls (four DSPs). For more information on this, refer to the error message %C542-1-INSUFFICIENT_DSPS (registered customers only) in the Error Message Decoder (registered customers only)
The compand-type a-law command does not exist on the CLI for a BRI port.
This bug restricted the use of the
to North America, as it resulted in the wrong compand decoding being applied and caused distorted voice. It was introduced in Cisco IOS Software Releases12.2(2) and 12.2(3)T, and corrected in the 12.2(5) and 12.2(8)T releases.
One of the applications of the BRI VICs is shown in this example. Observe that the BRI VIC can be directly connected to the PSTN or the ISDN PBX.
Note: The Cisco IOS software releases provided are typically the minimum version required to support the platform, module, or feature in question. To find out a complete list of Cisco IOS Software releases a feature, module, interface card, or chassis is supported in, refer to the Software Advisor (registered customers only) tool.