# Direct Inward System Access (DISA)

## Description

Direct Inward System Access (DISA) lets external callers access the system by using a special trunk. The system sees the DISA trunk as a station with its own Class of Service and Class of Restriction. Calls that enter the system on DISA trunks have access to a variety of system features. DISA trunks can be assigned account codes to provide a high degree of security or additional options.

A DISA trunk can be programmed as an answer point for other trunks (such as Direct-in lines) to give those trunks access to the DISA facilities. If required, a DISA trunk can be used as a night answer point. In all cases, the DISA trunk can be assigned account codes to provide a high degree of security or additional options.

## Conditions and Feature Interactions

- The outside caller must use a DTMF telephone.

- Features requiring a switchhook flash are not available.

- A DISA facility can be allotted two different directory numbers.

- A DISA directory number can be assigned either a forced account code, an optional account code, or no account code. See Account Codes Verified and Non-verified for more information.

- Only three successive attempts can be made to enter a valid account code during a DISA call. The use of the # recovery code is barred to the user after the third attempt.

- If extended by the attendant in a serial call sequence, the DISA user loses the ability to use the # recovery code.

- DISA calls are subject to the restrictions of the interconnection restriction table.

- The same set of personal account codes is valid for all DISA trunks at the same location.

- DISA users cannot use the Group Page feature.

- SIP devices and SIP trunks cannot make DISA calls over IP trunks.

- Calls cannot be forwarded to a DISA directory number.

## Programming

1. System Access Points form

Enter a DN for the DISA trunk in one of the following fields:

- DISA Forced Account Code - Directory Number (forces incoming callers to enter an account code)

- DISA Directory Number (no account code required)

2. System Options form

Set the DISA log-in failure timer and lock-out values.

2. DISA Number Lock-Out Timer

3. DISA Failed Attempts Before Lock-Out

3. Independent Account Codes form (DISA Forced Account Code only)

- If you entered a DN in the DISA Forced Account Code- Directory Number field (step 1), create an Independent Account Code number and assign it an appropriate COS and COR.

4. Trunk Attributes form

- Select a Trunk Service Number.

3. If you programmed DISA without a forced account code ("DISA Directory Number" field in step 1), assign an appropriate COS and COR for the trunk.

4. For non dial-in trunks, assign the DISA DN (created in step 1) as the answer point for Day, Night 1, and Night 2 service.

5. Digital Trunks form

- Assign the Trunk Service Number (step 3) to the required trunks.

## Device Support

All devices

## Operation

To make a DISA call:

1. Lift the handset.

2. Dial the DISA number.

3. If required, dial the account code feature access code and the account code digits.

4. Dial the desired facility.

5. If your call cannot be completed, do one of the following:

6. To abandon the call, hang up.

7. To make another DISA call, dial the # recovery code and dial another number.