Trunk Circuit Descriptors - Digital CO

Purpose:

The Digital CO Trunk Circuit Descriptors form is used to assign signaling and timing parameters to groups of DS1 CO trunk circuits using channel associated signaling (CAS).

Use this form when performing the following tasks:

 

Field Descriptions

Parameter

Description

Default Value

Number

Enter a number from 1 to 32 to uniquely identify each entry.

Blank

Line Start Type

Select the appropriate start type for the line.

Ground

Guard Timer

Enter the amount of time for which a trunk is unavailable for seizure following a release, in increments of 50 ms. This time is required to allow the trunk to clear before re-seizing. For Loop Start trunks, a value from 800 to 1600 should be chosen. For Ground Start trunks, a value from 100 to 200 should be used.

100 ms

Ignore Far End Disconnect

Select "Yes" or "No" to indicate if ground start trunks are to ignore or respond to a far-end disconnect signal.

No

Disconnect Timer

Enter the minimum length of a far-end disconnect signal. Allowed values are from 100 ms to 4000 ms in 50 ms increments. This timer must be longer than the Flash Timer.

500

Ringing Expected

Select "Yes" to indicate that ringing is necessary for an incoming seizure to be valid. Applies to DS1 CO trunks only.

Yes

Seize Timer

Enter how long the system will wait for a "seize acknowledge" before initiating a maintenance alarm. Allowed values are from 1 to 480 units (50 ms - 24 sec), each unit being equal to 50 ms.

(200 UNITS) 10 s

Address Signaling

Select "DTMF" or "Loop" to indicate whether the trunks use loop signaling or DTMF signaling.

  • Note: When systems are connected via T1/D4, the address signaling must match on either end of the connection. If one end is programmed as Loop and the other as DTMF, the dialed digits will not be translated by the receiving system, and the call will fail.

DTMF

Fake Answer Supervision After Outpulsing

Used to complete the audio connection after outpulsing if the trunk does not provide answer supervision. Select "Yes" to cause the system to provide answer supervision immediately after outpulsing. Select "No" to cause the system to wait for answer supervision from the far-end.

Yes

Release Supervision Expected

Select "Yes" to indicate that release supervision is provided from the far-end.

Yes

Ignore Answer Supervision

Specifies whether the trunk circuits are to expect answer supervision from the far-end. Select "Yes" to indicate that answer supervision is not expected. Select "No" to indicate that answer supervision is to be provided from the far-end.

Yes

Audio Inhibit Until Answer Supervision

Used to prevent a DTMF receiver, in line split mode, from being connected between the originating party and the outgoing trunk during the digit outpulsing phase of the call processing cycle. Select "Yes" to indicate that the audio path will only be connected after answer supervision has taken place.

Yes

Far End Connection

Not applicable to this release.

Local Office

Drop Digit Rcvr for Outgoing Audio Before Ans Sup

This option allows DTMF digits to be sent from a telephone to the CO without having to wait for or fake answer supervision. It also allows the system to provide exact call detail through SMDR by using the answer supervision signals provided by the CO.

Select "Yes" for credit or calling card calls, calls that require pin numbers, and equal access calls. For example, if the CO recognizes a calling card call, it will send either a tone or recorded message. Once the user enters a valid card number, the call proceeds and answer supervision is returned when the called party answers.

No

Flash Timer

Enter a value between "200" and "700" milliseconds in increments of 50 milliseconds. This timer specifies the duration of the single trunk flash or each of the flashes for a double trunk flash. For a double flash, the time between flashes is hard-coded at one second.

300 ms