Comdial and FXT Spezifikationen PDF herunterladen (Seite 86)

Direct Inward System Access (DISA)

DISA is a FXT enhancement option that allows outside callers to directly call a station or access certain internal

system features, including all line groups and ARS. The system allows up to eight DISA lines to be active at the

same time. To prevent fraudulent access and unauthorized use, the caller must use an authorization code and

system access code to gain access to outside lines as well as many of the advanced telephone features. The

authorization and access codes are from one to six digits (including pauses). You can use any of the digits zero

through nine.

The system denies access, and routes a DISA call to a preprogrammed device such as a station telephone, or

proprietary voice mail, under the conditions listed below:

•

a caller dialing an invalid authorization code,

•

a caller dialing restricted or invalid features,

Comdial has taken reasonable steps in the design of all product features, including DISA, which protect against

unauthorized or fraudulent access to, or use of, a system, or which protect against unauthorized, fraudulent or

unaccounted-for access to, or use of, long distance lines. However, no system is entirely invulnerable or

immune from unauthorized or fraudulent access or use, or unaccounted-for access or use, and therefore Comdial

disclaims any and all liability, and makes no warranty, express or implied, relating to unauthorized or fraudulent

access or use, or unaccounted-for access or use.

NOTE: Comdial engineers do not recommend DISA for use on loop start lines without disconnect

supervision. While DISA will function, Comdial will not be liable for its performance under

any condition where disconnect supervision is not provided.

NOTE: Callers that use DISA to access a line group and place calls (line to line calling) may

experience low audio levels on their calls due to the normal line resistance of CO lines. A low

audio level is usually only noticeable on long line loops. If signal loss is a problem at a

particular site, the installer may need to add a line amplifier (repeater) in the DISA line.

In regard to the above note, the system software adds +3dB of gain to the DISA lines as a default setting, and

provides a means for the installer to disable this gain if necessary. The software also provides a means by which

DISA callers can pre-select the gain on a DISA line before they select the line for use. They can dial a code to

select either 0dB, +3dB, or +6dB of gain.

It is important to note that uncompensated line-to-line DISA connections often exhibit low audio levels due to

double loop copper losses. While adding gain to these connections will sometimes improve audio signal levels,

the added gain may also result in circuit instability in some connections. This instability presents itself as a

singing sound that can interfere with dialing or voice communications. If callers experience dialing problems or

hear a singing sound in their calls, they should select a lower gain setting for use.

6 – 32 General Description

GCA40–215 General Description

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Comdial and FXT Spezifikationen Seite 86