# Setting CAS R2 BACK DIGITS Variable

### **Applies to version(s): v2.7.**

**Applies to version(s): v2.7.**

Once the CAS R2 stack and script are created, you must set the backward digits string to instruct the stack about the sequence of tone requests that must be sent when acting as the backward end. Refer to CAS R2 BACK DIGITS for more details. There are two methods to configure the backward digits string.

## Method 1: Setting script BACK DIGITS variable

The backward digits string can be configure directly inside a CAS R2 script. This means that all CAS R2 stacks using this script will benefit from the same configuration.

1- Click **CAS R2** in the navigation panel

2- Click the **Scripts** tab

3- Click **Edit** next to the desired configuration

4- Edit the "**BACK_DIGITS**" variable value to the desired value, please refer to CAS R2 BACK DIGITS for description of valid digits.

## Method 2: Setting stack BACK DIGITS variable

The backward digits string can also be overwritten on a per E1/CAS R2 stack base.

1- Click **CAS R2** in the navigation panel

2- Click **Edit** next to the desired stack

3- Click **Editing Variant Script Variable** to expand area

4- Click **Create New Variable**, select **BACK_DIGITS** variable name from the drop box and enter the desired value