Scenario#23 – Fax Issues for ATA

Fax machines connected to ATA were not working. The first thing I checked on the gateway…is fax-relay was being used or fax protocol cisco was configured? Fax-relay is NOT supported by ATA. This is what I found at the Voice gateway: voice service voip allow-connections h323 to sip allow-connections sip to h323 allow-connections sip toContinue reading “Scenario#23 – Fax Issues for ATA”

IOS 15.1 Toll Fraud feature

A new feature has been introduced in Cisco IOS® Software Release 15.1(2)T to guard against the incidence of toll-fraud on Voice GateWays (VGWs) installed with Cisco IOS. Starting with IOS 15.1(2)T and newer releases of IOS based on this version, the toll-fraud prevention settings are the default behavior of Cisco IOS-based VGWs. Behavior Before 15.1(2)TContinue reading “IOS 15.1 Toll Fraud feature”

Scenario#22 – ISDN user busy 0x8091

This was an interesting scenario where incoming calls were getting ‘user busy’ message at the gateway and an engage tone was heard at calling party side. *Aug 18 08:36:53.581: ISDN Se0/0/0:15 Q931: RX <-CALL_PROC pd = 8  callref = 0x8D7E Channel ID i = 0xA9839E Exclusive, Channel 30 *Aug 18 08:36:54.997: ISDN Se0/0/0:15 Q931: RXContinue reading “Scenario#22 – ISDN user busy 0x8091”

Scanario#21 – VG224 Fax Issues

Customer reported a fault that several fax machines which were working fine last week have suddenly stopped working. All they were getting for incoming faxes was just the header. No content of the actual fax. Rule of thumb – anything which was working before and not working now means something must have changed. I jumpedContinue reading “Scanario#21 – VG224 Fax Issues”

Troubleshooting Ringback Issues H323

Before we dive into troublehsooting let’s keep the following in mind when an ISDN call progress. If A is making a call to B so A is calling party and B is called party. The ISDN messages negotiated between the two would be as follows: A —-> Setup —-> B B —-> Call Proceeding —->Continue reading “Troubleshooting Ringback Issues H323”

Scenario#10 – Phones showing Incorrect time

I don’t remember how many times I came across customers complaining that their phones are either x minutes ahead or x minutes behind the normal time. This is what I do whenever I come across time issues. This is for applicance based Call manager (5.x, 6.x, 7.x, 8.x) Go to OS Admin > Settings >Continue reading “Scenario#10 – Phones showing Incorrect time”

Blocking Incoming Calls using Translation rule

How to block an incoming number on an H323 gateway? For an MGCP gateway this is not possible as CUCM cannot block incoming calls. Configure the following to block calls from 08009782222. Voice translation-rule 400 rule 1 reject /08009782222/ Voice translation-profile BLOCK translate calling 400 dialpeer voice 1 pots incoming called-number . call-block translation-profile incomingContinue reading “Blocking Incoming Calls using Translation rule”

H323 Dial Peer made simple

H323 dial peers play an important role in Call routing though a H323 gateway. Understanding dial peers is very crucial for Call routing or any dial plan design. Most of the time people are confused between POTS and VoIP dialpeers and how they should be used. I will try to make the concept as easyContinue reading “H323 Dial Peer made simple”

Scenario#1 – VG224 – Strange DTMF behaviour

Problem description: One of my customer reported an issue with their VG224. All Polycom conference phones connected to the Vg224 were facing an strange issue of DTMF tones not recognized by PSTN. Users trying to get into a MeetMe conference were having  tough time as their pin was not getting recognised. Analysis & Observations: ThisContinue reading “Scenario#1 – VG224 – Strange DTMF behaviour”

H323 Call Preservation

H323 gateway is a non-survivable endpoint. This means an active call will drop if any call manager goes down. This default behavior of an H323 gateway can be changed by playing with few settings at the CUCM and gateway. At gateway: voice service voip h323 call preserve At CUCM: Allow TCP Keepalive for H323  =Continue reading “H323 Call Preservation”