# Routing Emergency Calls to Multiple Gateways

## Description

The analog gateway can handle local 911 calls for IP phone users who are physically located in the same city as the analog gateway. Due to the limitation on the number of routes allowed in an ARS Route List (six), a maximum of five remote analog gateways can be selected when a 911 call is routed through the route list. This topic describes how to route 911 calls to more than five analog gateways.

## Programming

This example describes how to use a loopback IP trunk to insert a specific ARS leading digit using the default account code feature on 911 call. The newly inserted ARS digits are used to route 911 calls to the corresponding analog gateway.

### Setup conditions

- All IP trunks have been successfully established to all remote analog gateways.

- All IP phones are registered to the main MiVoice Business system.

- For demonstration purposes, route 20, XNET trunk group 10 and digit modification number 10 are newly created for main MiVoice Business loopback.

- Chicago and New York are remote locations using analog gateway. One may extend the idea to multiple analog gateways.

### Programming steps on the main MiVoice Business system

1. Create a virtual loopback IP trunk.

- In IP/XNET Trunk Groups, create a new XNET Trunk group 10 and assign the local PBX /main MiVoice Business system number in the field of PBX number. Enter the local profile number,max networks hops as one would normally do on a regular IP trunk.

- In ARS Routes, select a new route number 20 and enter 10 in the field of Xnet trunk group number and 10 in the field of digit modification number.

2. Program the virtual loopback trunk to insert default account code. In the ARS Digit Modification Plans form, select the digit modification number 10, and enter <D> in the field of "Digits to be inserted".

   NOTE: For the field of "number of digits to absorb", this depends on how one routes traffic original. Typically, 0 is expected.

3. Define a range of ARS leading digit that one would use to route 911 calls. You can create the following ARS mapping:

- ARS leading digit 81 followed by 911 to route call to Analog Gateway at Chicago

- ARS leading digit 82 followed by 911 to route call to Analog Gateway at New York.

NOTE: If Analog gateway is clustered, one may consider to use CEID digits as its ARS leading digit followed by 911 to route calls to the appropriate Analog Gateway accordingly.

4. Map the specific ARS leading digit from Step 3 to the corresponding account code index in Default Account Codes. For example, in the Default Account Codes form,

- enter 81 next to account code index 1 for Chicago user;

- enter 82 next to account code index 2 for New York user

5. Associate each group user with the appropriate account code index in station attributes. For example, In Station Attributes,

6. enter 1 in the column of default acct. code for all Chicago's extensions,

7. enter 2 in the column of default acct. code for all New York's extensions.

6. Create a route list (e.g. 11) so that local and remote analog Gateway can differentiate based on COR. In the ARS Route Lists, select route list number 11 and assign the first and second choice route. The first choice should be a local 911 route for local user and the second choice should be for all remote Analog Gateway (route 20)

   NOTE: You must set up proper COR in a way that local user can only access the first choice, while all other users designated for remote Analog Gateway location should have access the second choice only.

7. Create the following 911 ARS Digits Dialled for various routing purposes:

In ARS Digits Dialed, create the following leading digits:

- 911 or 9911 (depending on your local dialling scheme or preferences) using route list 11.

- 81911 or 819911 and select the existing IP trunk route to Chicago

- 82911 or 829911 and select the existing IP trunk route to New York

NOTE: Consider when to absorb the leading digits inserted by default account <D> for Step 7b and Step 7c. Do not forget to create a similar 911 route in Chicago and New York's analog gateway accordingly.

## Considerations

The number of VOIP calls defined in XNET ICP/PBX Networking must take the additional loop trunks into consideration. Consider the number of simultaneous 911 calls and regular calls to/from analog gateway due to bandwidth utilization.