Direct Inward System Access (DISA)

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Direct Inward System Access (DISA)

Functional description
To compensate for shortcomings of the DIL and DDI, this function enables the external subscriber to make a call by directly dialing the extension or trunk subscriber without assistance of the operator. The following two types of services are available. The external subscribers need additional dialing and have to get through authorization procedure (can be omitted).

Line DISA (Method that makes up for shortcoming of DIL, which does not support direct call to the subscriber) – Used for APTC, ALTC-RD, and BRIT.

When the concerned trunk is assigned as the DISA and the incoming call is received, DISA service is provided without condition.

DDI DISA (Method that makes up for shortcoming of DDI, which is limited by numbering plan of the outgoing station) – Used for the remaining trunk type.

DISA service is provided when the system makes a call to the designated DISA representative number through DDI.

Operating procedure
Line DISA

[When the authorization code is not assigned]

The DISA line receives a call from the designated trunk.
The external subscriber hears the assigned DIS dial tone (can be replaced with the announcement line). If they do not match, it will be processed by the vacant number calling option of the incoming designation for abnormal trunk incoming.
The external subscriber makes a call to the intended extension or trunk subscriber.
When the wanted subscriber answers, make conversation.

[When the authorization code is assigned]

The DISA line receives a call from the designated trunk.
If the DISA authorization code exists, the external caller will hear DISA authorization dial tone (can be replaced with the announcement line).
The external subscriber dials the DISA authorization code that was given to him/her.

4 If the DISA authorization code matches with the code assigned to the system, the external subscriber hears the assigned DIS dial tone (can be replaced with the announcement line). If they do not match, it will be processed by the vacant number calling option of the incoming designation for abnormal trunk incoming.

5 The external subscriber makes a call to the intended extension or trunk subscriber.

6 When the wanted subscriber answers, make conversation.

DDI DISA

[When the authorization code is not assigned]

Calls the DISA assigned to the system using DDI.
The external subscriber hears the assigned DIS dial tone (can be replaced with the announcement line). If they do not match, it will be processed by the vacant number calling option of the incoming designation for abnormal trunk call incoming.
The external subscriber makes a call to the intended extension or trunk subscriber.
When the wanted subscriber answers, make conversation.

[When the authorization code is assigned]

Calls the DISA assigned to the system using DDI.
If the DISA authorization code exists, the external caller will hear DISA authorization dial tone (can be replaced with the announcement line).
The external subscriber dials the DISA authorization code that was given to him/her.
If the DISA authorization code matches with the code assigned to the system, the external subscriber hears the assigned DIS dial tone (can be replaced with the announcement line). If they do not match, it will be processed by the vacant number calling option of the incoming call designation for abnormal trunk call incoming.

5 The external subscriber makes a call to the intended extension or trunk subscriber.

6 When the wanted subscriber answers, make conversation.

Service conditions
For the abnormal incoming call, processing like the attendant incoming call can be processed according to the option for each route.

Direct call service between trunks can be allowed or prohibited.

All DISA trunk incoming calls can be diverted to the designated subscriber. (See DDI divert function)

The DDI DISA representative number can be produced by the paging group.

Rep. No: Should be included in extension numbering plan.
Service Type: DISA
The remaining items are irrelevant.

Data generation
Assign trunk type

[4.1 Trunk Information ⇒Type item]

Trunk route separation

[4.1 Trunk Information ⇒ Trunk Route]

[4.7 Trunk Route Assign]

Connection Allow/Deny Option between Routes

[4.12 Inter Route Connection Allow/Deny]

Assign line DISA

[4.1 Trunk Information – Trunk Option ⇒ 2. DISA Line

Assign a DISA representative number

[6.4 Calling Group ⇒ Service Type]

Assign a DISA authorization code

[4.14 DISA Authorization Code]

Changing DISA dial tone

[2.4 System tone parameter] – DISA Dial Tone item

Changing DISA authorization code dial tone

[2.4 System tone parameter] – DISA Auto Code Dial Tone item

Service Assign per Day/Night Mode for Abnormal IC trunk Call

[4.10 Trunk Route Base IC Day/Night Option]

Interaction