ISDN E1 PRI configuration for PSTN

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Apr 8th, 2003
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I am proposing a solution of remote access to our customer with CISCO router 3745 and NM-CE1-B ISDN PRI module.Can this port receive the PSTN data calls also.Can the same interface be configured for receiving ISDN/PSTN calls at the same time.Remote users are dialing to the ISDN PRI through their PC and an external PSTN Modems.Give me some sample configuration.


Network Engineer NTS


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Yes you could allow both ISDN/PSTN users to the same E1, provided if the router has Async ports.

Hope this config helps.

Good Luck



controller e1 1/0

pri-group timeslots 1-31


interface Serial1/0:15

ip unnumbered Loopback0

encapsulation ppp

ip tcp header-compression passive

dialer idle-timeout 1500

dialer-group 1

isdn switch-type primary-net5

isdn incoming-voice modem

peer default ip address pool DIALPOOL

no cdp enable

ppp authentication pap chap

ppp multilink

sanjay.sangwan Wed, 04/09/2003 - 03:36
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HI thanks for the response.But do I need to put NM-30DM digital network module also in the router.I checked the cisco documentation which says that ISDN pri will divert the analog PSTN calls to these internal modems.Pls confirm


makchitale Wed, 04/09/2003 - 07:43
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Yes, you will need internal digital modems (NM-xDM) to terminate the analog calls.

When the call comes in on the PRI, based on the bearercap in the call setup message the analog call will be sent to the digital modem (isdn incomming-voice modem command under the D-channel does it)

Thanks, Mak.

kitog Wed, 04/30/2003 - 00:25
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Hi Sanjay,

Did it work for you?

I'm trying to set this configuration with AS5300 but when dialing in the call always act as a data call, even if i call from analog phone, and not voice call...

can you send some config example to help me?

Thanks, Kito.


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