Howto:FXS FXO trunk with IP22 media gateway and Cisco 1700 router

This article describes how to realize an analog trunk using Innovaphone FXS media gateway and Cisco router.

Applies To

This information applies to

• IP 22, V7

Build 09-70300.14 and later.

• Cisco 1700 router

IOS C1700-IPVOICEK9-M, Version 12.4(19b)

More Information

Problem Details

In this case Innovaphone IP22 is used as FXS media gateway with a Cisco 1700 Router to realize an analog PBX extension over an IP network.

The VoIP signaling protocol used is SIP.

Cisco FXO gateway must forward incoming calls to IP22. This automatic mechanism is realized with PLAR OPX feature. The private line automatic ringdown Off-Premises extension allows remote FXS devices to appear to a central PBX as a directly connected extension. When the FXO port detects a ring from PBX, the Cisco router sends a VoIP call setup to IP22 but it does not take the FXO port off-hook. As a result, the PBX only sees the call answer signal when IP22 FXS port is picked up. In the same way, IP22 must forward outgoing calls to FXO gateway. PLAR endpoints are statically configured and do not require the user dialing to connect calls. The connection plar creates a VoIP call without digit dialing.

Installation

Configuration

Connect devices as show in figure.

Numbering scheme of analog ports (necessary to create plar connection).

Innovaphone IP22	number	called number when off-hook
TEL1	103	203
TEL2	102	202

Cisco 1700	number	called number during incoming PBX ring
FX0 voice-port 2/0	202	102
FX0 voice-port 2/1	203	103

CISCO CONFIGURATION (network configurations is omitted)

FXO Voice port, command line configuration:

voice-port 2/0
input gain -6
output attenuation 6
no non-linear
no vad
playout-delay nominal 100
playout-delay mode fixed
cptone IT
timeouts call-disconnect 1
timeouts wait-release 1
timing guard-out 300
connection plar opx 102   <--- incoming calls from PBX generate calls to phone number 102; Cisco SIP dial-peer number 2 is matched
!
voice-port 2/1
input gain -6
output attenuation 6
no non-linear
no vad
playout-delay nominal 100
playout-delay mode fixed
cptone IT
timeouts call-disconnect 1
timeouts wait-release 1
timing guard-out 300
connection plar opx 103   <--- incoming calls from PBX generate calls to phone number 103; Cisco SIP dial-peer number 2 is matched

Dial Peer, command line configuration:

dial-peer voice 2 voip                  <--- when this dial-peer is matched a SIP INVITE is sent to Innovaphone Media Gateway
description SIP_CALL_TO_IP22                 
destination-pattern 1..
modem passthrough nse codec g711alaw
session protocol sipv2
session target ipv4: __IP22__IP_ADDRESS__
session transport udp
incoming called-number .
dtmf-relay rtp-nte
codec g711alaw
fax rate disable
fax protocol pass-through g711alaw
no vad
!
dial-peer voice 3 pots
description FROM_IP22_TEL3
destination-pattern 203
port 2/1
!
dial-peer voice 4 pots
description FROM_IP22_TEL2
destination-pattern 202
port 2/0

SIP UA configuration:

sip-ua 
disable-early-media 180
max-forwards 10
retry invite 3
timers expires 60000
no suspend-resume