Configuring ISDN PRI Voice Ports

We discussed the analog VICs modules such as the E&M, FXO, and FXS, but larger organizations that need higher-density interfaces to the PSTN or PBX typically use digital T-1/E-1 modules. The following is a list of digital voice interfaces and supported platforms:

• 
  
  Digital T-1/E-1 Packet Voice Trunk Network Module, NM-HDV (VWIC-1MFT and VWIC-2MFT) Cisco 2600 and 3600 series.
• 
  
  Digital voice interface card (DVM) Cisco MC3810.
• 
  
  Octal or Quad T-1/E-1/PRI feature card Cisco AS5300 universal access server.
• 
  
  Channelized trunk card and voice feature card Cisco AS5800 universal access server.
• 
  
  T-1/E-1 high-capacity digital voice port adapter Cisco 7200 and 7500 series.

As with analog, the VICs are inserted into the VNMs to create the digital T-1 voice module for the Cisco 2600 and 3600 series routers. The Cisco 1760 router can use the individual VWIC-2MFT-T-1 card as an interface to a PBX or PSTN for digital connectivity. The card uses a RJ-48 crossover cable for connection to a PBX. The pinouts are listed below:

• 
  
  Pin 1 RX ring
• 
  
  Pin 2 RX tip
• 
  
  Pin 4 TX ring
• 
  
  Pin 5 TX tip

The items needed for configuration of the controller settings are the following:

• 
  
  Line interface T-1 or E-1
• 
  
  Signaling interface FXO, FXS, or E&M and ISDN PRI or BRI—Q.SIG or CCS
• 
  
  Line coding AMI or B8ZS for T-1, and AMI or HDB3 for E-1
• 
  
  Framing format SF (D4) or ESF for T-1, and CRC4 or no-CRC4 for E-1
• 
  
  Number of channels

The controller configuration steps for an ISDN PRI connection to a PBX follow:

router# config terminal
router(config)# isdn switch-type basic-ni1
router(config)# controller T-1 1/0
router(config-controller)# framing esf
router(config-controller)# clock source internal
router(config-controller)# linecode b8zs
router(config-controller)# pri-group timeslots 1-24

This produces the following configuration:

(Partial Router configuration)
!
hostname router
!
memory-size iomem 15
voice-card 1
!
isdn switch-type ni1
!
controller T-1 1/0
framing esf
clock source line
linecode b8zs
pri-group timeslots 1-24
!
interface Serial1/0:23
no ip address
no logging event link-status
isdn switch-type primary-ni1
isdn incoming-voice voice
isdn T310 60000
no cdp enable
!
voice-port 1/0:23
!