How do I set up some simple Codian ISDN GW rules to place calls from IP to ISDN and ISDN to IP?

Introduction

This article relates to the Cisco TelePresence ISDN GW 3241 and Cisco TelePresence ISDN GW MSE 8321 products.

Q. How do I set up some simple Codian ISDN GW rules to place calls from IP to ISDN and ISDN to IP?

A. The dial plans work on 'first match' routing. This means that, for a given call direction (IP->ISDN or ISDN->IP) the ISDN gateway will start at the top of the dial plan and work its way down the list of rules until one matches: then it will perform the action specified in that rule. You can alter the order of rules (depending on the build that your ISDN gateway is running) by dragging and dropping rule names, using the 'up' and 'down' links to the right of each rule, or both. For more information about dial plans, see the online help.

Here are some basic examples:

IP to ISDN rules

Example 1

You are using a gatekeeper and you have set the Codian ISDN Gateway dial plan prefix to 99 (for example). You want people to be able to dial 99 + a PSTN number, and for the Codian ISDN Gateway to dial the PSTN number on its own.

You create an IP to ISDN dial plan rule like this :

• Called number matches : 99 (D+)

• Call this number : $1

Explanation: $1 refers to the first bracketed group in the number match field. This is D+, which means one or more of any digit. By putting the 99 first we exclude it from the D+ group, which means we are left with a valid PSTN number to dial. So the user could dial 990149454339 from their phone and the ISDN Gateway would strip the 99 and dial 0149454339 over the PSTN.

Example 2

You are not using a gatekeeper. Some other H.323 gateway (e.g Codian MCU or Cisco CUCM) is routing 4-digit E.164 numbers to the Codian ISDN Gateway. You know that if you prefix these with a certain group of digits you will turn them into a valid PSTN number that the ISDN Gateway can dial.

You create an IP to ISDN dial plan rule like this :

• Called number matches : DDDD (note that no brackets are needed as we are going to use all the digits we received)

• Call this number : 01 49 45 $A ($A means all the digits we received)

Explanation: DDDD is a group of any 4 digits. $A is all the digits that the ISDN Gateway received from the H.323 device placing the call to it. So if a Codian MCU placed an H.323 gateway call to the ISDN Gateway with the digits 4339, the ISDN Gateway would dial 01 49 45 43 39 over the PSTN.

ISDN to IP rules

Example 3

You are using a gatekeeper. Your Telco has allocated you a block of 20 direct dial (DDI) numbers in the range 01 49 45 43 30 to 01 49 45 43 49, of which the final 6 digits are presented by the PRI. You have 20 H.323 endpoints and you register them with your gatekeeper with E.164 numbers 1030 to 1049. You want ISDN endpoints on the PSTN to be able to dial your H.323 endpoints directly using the DDI numbers.

You create an ISDN to IP dial plan rule like this :

• Called number matches : 4543 (DD) (you could use (D+) here instead of (DD), it doesn't matter if you know you are going to get 6 digits from the telco)

• Call this number : 10 $1 (dial 10 plus the first bracketed group, i.e the last 2 digits in the DDI number)

Explanation: An ISDN endpoint calls 01 49 45 43 39 and the call arrives on your PRI presenting the digits 45 43 39. To place the IP call via your gatekeeper, you need to strip off the 45 43 and call with the remaining 2 digits prefixed with 10, which matches the E.164 number of your H.323 endpoint.

Example 4

You are not using a gatekeeper. You have the same DDI arrangement as in example 3, but this time, you have 20 conferences on your MCU with numeric IDs 4330 to 4349. You want ISDN endpoints on the PSTN to be dial directly into these conferences, using your DDI numbers (so when they dial 01 49 45 43 30 they are connected direct to conference 4330).

You create an ISDN to IP dial plan rule like this :

• Called number matches : 45 (D+)

• Call this number : 194.178.0.5 : $1 (194.178.0.5 is the IP address of your MCU, this syntax causes the ISDN gateway to place an H.323 gateway call to extension $1 at that IP address)

Explanation: When the ISDN endpoint dials 01 49 45 43 30 (for example), the digits 45 43 30 arrive on the PRI. The ISDN gw strips the 45 and makes a gateway call to 194.178.0.5, E.164 extension 4330, which connects the call direct to conference 4330.

Related Information

• Technical Support & Documentation - Cisco Systems