# Trunk Circuit Descriptor - Digital E&M

## Purpose

The Digital E&M Trunk Circuit Descriptor form is used to define the characteristics of the DS1 trunk circuits used for Channel Associated Signaling (CAS) over DS1 E&M trunks.

Use this form when performing the following tasks:

- Program T1/D4 Trunks

- Program Embedded T1/D4 Trunks

NOTE: The operating characteristics for all trunks are defined by the respective trunk circuit descriptor form. There are 32 trunk circuit descriptor numbers available. These must be shared between all trunks in the system. As well, each circuit descriptor number assigned must be unique. MITEL recommends that the circuit descriptor numbers be allocated to each type of trunk in blocks. For example, CO trunks may be allocated circuit descriptor numbered 1 through 4, E&M trunks numbered 5 through 12, DS1 DID trunks numbered 13 through 21, and so on.

## Field Descriptions

Parameter | Description | Default Value
Number | Enter a number from 1 to 32 to uniquely identify each entry. | Blank
Call Collision Handling | Select whether "Normal" or "AT&T" method of glare handling is to be used. | AT&T
AT&T Call Collision Handling | If the AT&T method of glare handling is used, this parameter defines whether this end is to " Backoff" or " Nobackoff". | Backoff
Ignore Far End Disconnect | Select whether the trunks are to ignore or respond to a far-end disconnect signal. | No
Release Acknowledge Timer | Enter the amount of time the system will wait for a release acknowledgement from the far-end. Values range from 40 to 2400 UNITS. One unit equals 50 ms. | (80 UNITS)4 s
Address Signalling | Select whether the trunks use Loop 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. | Loop
Disconnect Timer | Enter the minimum length of a far-end disconnect signal. Allowed values are from 100 ms to 900 ms in 50 ms increments. This timer must be longer than the Flash Timer. | 900 ms
Incoming Start Type | Select whether the trunk is immediate, delay dial, or wink start on incoming calls. | Wink
Dial Tone on Incoming Seize | Select if dial tone is to be returned when the trunk is seized by the far-end. | No
Outpulse Delay Timer | Enter the duration of the delay before outpulsing commences after a seizure. Allowed values are from 100 ms to 2000 ms in 10 ms increments. | 800 ms
Outgoing Start Type | Select if the trunk is to provide wink start, immediate dial, delay dial, or delay dial with integrity check on outgoing calls. | Wink
Supervision Timer | Enter the expected duration of a supervision signal from the far-end. Values range from 200 to 12750 ms. 200 ms to 1000 ms is used for immediate dial trunks, 200 ms to 12750 ms for wink start trunks, and 4500 ms to 12750 ms for delay dial and delay dial with integrity check trunks. Values change in 50 ms increments. | 200 ms
Maximum Wink Timer | Enter the maximum duration of the wink signal received from the far end. Values range from 300 to 4000 ms, and change in 50 ms increments. 300 ms to 450 ms is used for wink start, immediate or delay dial trunks, and 300 ms to 4000 ms for delay dial trunks with integrity check. | 400 ms
Minimum Wink Timer | Enter the minimum duration of the wink signal received from the far end. Allowed values are from 50 ms to 150 ms in 50 ms increments. | 100 ms
Guard Timer | Enter the amount of time for which a trunk will be unavailable for seizure following a release, to allow the trunk to clear before reseizing. Allowed values are from 100 ms to 6000 ms in 50 ms increments. | 500 ms
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. | No
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. | No
Release Supervision Expected | Select "Yes" or "No" to indicate whether release supervision is 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. Select "No" if a DTMF receiver, in linesplit mode, IS to be connected between the origination party and the outgoing trunk during digit outpulsing. | Yes
Far End Connection | Not applicable to this release. | Main PBX
Facility Type | Select "Yes" or "No" to indicate if the far-end facility is digital or a combination of digital and analog. | Combination
Minimum Flash Timer | Enter a value between "100" and "250" milliseconds, in increments of 10 milliseconds, to define the minimum flash time required in order for the peripheral software to detect a recall. | 250 ms
Maximum Flash Timer | Enter a value between "200" and "800" milliseconds, in increments of 10 milliseconds, to define the maximum flash time required in order for the peripheral software to detect a recall. | 200 ms
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
AB Signalling Bit Inversion | Select "Yes" to indicate that the trunk is a Private Line Automatic Ringdown trunk. | No
Manual Ringdown Trunk | Select "Yes" to indicate that the trunk is a Manual Ringdown (MRD) trunk for use with the Voice Trader Application Platform (VTAP). | No
Far End Disconnect Not Required Before Initiating New Call | Select "Yes" if the far end T1/E1 CAS link does not need to return to idle before a new call is initiated on the link. Otherwise, the near end must wait until the far end acknowledges a disconnect signal or the session timer matures. Before changing the state of this option, use the BUSY maintenance command to temporarily remove the circuit from service. Use the RTS command to return it to service after the change. NOTE: Enabling this option limits circuit use to either Direct Trunk Select lines or answer points. Loop dialing is not supported. | No
Ring until Answer | Select "Yes" for E1 CAS PLAR trunks to continue ringing until called party answers or the ringing timer in the trunk Class of Service expires. The default (No) rings only while the far end signals a seize. | No