Problem with calls between analog and Ip Phones

Answered Question
Jan 8th, 2008
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Hi all,


I'm using a CCM 4.1.3 and I have a 2821 router as

voice gateway with IOS ver 12.4 which has an EVM-HD-8FXS module with a EM-HDA-6FXO card.


WHEN AN ip phone number 4707 calls an analog phone 4801 (connected to the EVM-HD-8fxs module) the call

goes through, but when the analog phone calls an IP phone the call

does not go through, even the router does not detect this call.


Could someone help?


The configuration of the dial-peer used are below:



dial-peer voice 4000 voip

preference 1

destination-pattern 4...

voice-class codec 1

session target ipv4:10.128.32.3

dtmf-relay h245-alphanumeric




dial-peer voice 4801 pots

destination-pattern 4801

port 2/0/1


Thanks in advance!

Correct Answer by pcameron about 9 years 4 months ago

'direct-inward-dial' should not be configured on analogue port types. It is intended to be used on digital ports such as PRI or BRI where a DNIS (called number) is passed from the external device, so there is no need to go off hook and play a secondary dial tone. If you configure it on an analogue port, all it does is stops the dial tone being played when the user takes the port off hook ... not good.


Based on the original description, a call can go from the CCM to the FXS port, but when they make the call from the FXS port to the CCM, nothing happens.


First thing to do - ensure you can ping the CCM from the gateway. An incorrect default gateway (for example) will allow traffic in one direction but not the other.


The most common reason why calls work in only one direction happens is due to the router having several IP addresses configured on it (sub interfaces on the FE, serial ports etc ...) and when it sends traffic to the CCM , by default it will use the IP address of the closest interface to the destination as the actual source address of the H225 traffic.


The call manager is configured to point to one of these IP addresses so calls from CCM to GW will work fine.


However, when the gateway originates a call, it uses a different source address to what the CCM is expecting, so it ignores the h225 setup message.


Try adding the command 'h323-gateway voip bind srcaddr ' to the actual interface the call manager has configured as the gateway IP address. This will force the gateway to use this IP address as the source address for all the H225 signaling and media traffic.


It sometimes pays to reset the gateway in the CCM config as well.

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j.huizinga Wed, 01/09/2008 - 02:23
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Hi,


First you have to check if the FXS detects off hook (sh voice call sum)


If it does you have to configure direct inward dial:

Something like:

dial-peer voice 1 pots

incoming called-number .T

direct-inward-dial

good luck,


Jan




Correct Answer
pcameron Wed, 01/09/2008 - 05:12
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  • Cisco Employee,

'direct-inward-dial' should not be configured on analogue port types. It is intended to be used on digital ports such as PRI or BRI where a DNIS (called number) is passed from the external device, so there is no need to go off hook and play a secondary dial tone. If you configure it on an analogue port, all it does is stops the dial tone being played when the user takes the port off hook ... not good.


Based on the original description, a call can go from the CCM to the FXS port, but when they make the call from the FXS port to the CCM, nothing happens.


First thing to do - ensure you can ping the CCM from the gateway. An incorrect default gateway (for example) will allow traffic in one direction but not the other.


The most common reason why calls work in only one direction happens is due to the router having several IP addresses configured on it (sub interfaces on the FE, serial ports etc ...) and when it sends traffic to the CCM , by default it will use the IP address of the closest interface to the destination as the actual source address of the H225 traffic.


The call manager is configured to point to one of these IP addresses so calls from CCM to GW will work fine.


However, when the gateway originates a call, it uses a different source address to what the CCM is expecting, so it ignores the h225 setup message.


Try adding the command 'h323-gateway voip bind srcaddr ' to the actual interface the call manager has configured as the gateway IP address. This will force the gateway to use this IP address as the source address for all the H225 signaling and media traffic.


It sometimes pays to reset the gateway in the CCM config as well.

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