1.16 Optional Device Features
1.16.6 Direct Inward System Access (DISA)
Description
An outside caller can access specific PBX features as if the caller is an SLT extension user on the PBX, when the incoming call destination is a DISA floating extension number assigned to each DISA message. The caller can have direct access to features such as:
•Placing an intercom call to an extension, operator or any floating extensions (e.g., modem for remote system administration, an external pager for TAFAS).
•Calling an outside party via the PBX.
•Operating some PBX remote features (e.g., FWD)
Outgoing Message (OGM)
When a call arrives on a DISA line, a prerecorded DISA message will greet and guide the caller.
Any extension assigned as the manager can record outgoing messages (OGMs). ( 
1.16.5 Outgoing Message (OGM))
DISA Intercept—No Dial
If the caller fails to dial any digits within a preprogrammed time period (DISA 1st Dial Time for Intercept) ( 
DISA Intercept Time [211]) following the outgoing message (OGM), the call is redirected to the operator extension.
DISA Built-in Automated Attendant Number (DISA AA Service)
After listening to the outgoing message (OGM), the caller may dial a single digit (DISA AA number). The destination for each DISA AA number can be assigned for each message. It is also possible to assign other DISA floating extension number as the destination (Multistep DISA AA Service).
If the caller dials a second digit within a preprogrammed time period (DISA 2nd Dial Time for AA), the DISA AA service is not employed.
DISA Security Mode and Available Features
If the DISA AA service is not employed, the caller may access the PBX features by entering the feature numbers. To prevent others from accessing the PBX features, it is possible to assign DISA security ( 
DISA Security Mode [732]). The features available depend on the preprogrammed DISA security mode as follows:
