# Digital Link Descriptors

## Purpose

The Digital Link Descriptors form defines the protocol characteristics of DASS II links and T1/D4 links. Both CEPT and DS1 trunk characteristics are defined by this form.

Use this form when performing the following tasks:

- Program Digital Trunks

CAUTION: Making changes in this form may result in dropped calls on the affected links. Limit changes to off-hours if possible.

## Conditions

- DASS II is only available in the United Kingdom.

## Field Descriptions

Parameter | Description | Default Value
Number | Enter a number (1 through 16) to uniquely identify the Descriptor. | Blank
Address for Message Control | Defines the direction of the command and response messages between two systems in an MSDN/DPNSS network. Select "A" or "B" to assign it to the local end of the link. The other end must be assigned "B" or "A" respectively as part of network configuration. This field only applies to MSDN/DPNSS. If the Integrated Digital Access entry is DASS II, this entry must be assigned "B" if the system is the end of the DASS II link; the entry is "A" only if the system is simulating the local exchange end of the link (i.e. during loopback checking). | Blank
BER - Maintenance Limit, 10**-n | Enter the exponent of the allowable Bit Error Rate (BER) in any 24-hour period. When the maintenance limit is reached a log is generated. The maintenance BER must be greater than the service BER. | 4
BER - Service Limit,10**-n | Enter the exponent of the allowable Bit Error Rate in any 24-hour period. When the service BER limit is exceeded, a maintenance log is generated. | 3
Data Call Alternate Digit Inversion | This field applies only to CEPT trunks running DPNSS. To disable ADI on data calls select "No". |
Framing Losses in 24 hrs - Maintenance Limit | Enter the number of short (50 ms.) out-of-synchronization periods tolerated before a maintenance log is generated. The maintenance framing losses must be less than the service slip losses. | 255
Framing Losses in 24 hrs - Service Limit | Enter the number of short (50 ms.) out-of-synchronization periods tolerated in any 24-hour period. When the service frame limit is exceeded, a maintenance log is generated. The link is returned to service after 10 ms in sync. | 9000
Integrated Digital Access | Select the signaling protocol to be used on the link to connect the local exchange. The following options are available: DPNSS, T1/D4, DASS II, APNSS, CEPT CAS, ISDN NODE, EURO GROOMER, BRI NODE. Select from one of the following: DPNSS to connect the link to a Digital Private Network Signaling System T1/D4 to connect the link via a T1/D4 trunk DASS II to connect the link to a Digital Access Signaling System #2 (a common channel signaling protocol designed for communications between a PBX and a CO). DASS II links are only available in the UK. APNSS to connect the link to an Analog Private Network Signaling System CEPT CAS to connect the link to Committee for European Posts and Telegraph (CEPT) Channel Associated Signalling (CAS) link. EURO GROOMER to connect the link to an Acculab Groomer gateway. BRI NODE to an embedded BRI module. ISDN NODE to allow the link to be connected to an embedded PRI module, PRI card, or an ISDN Gateway. | Blank
Vendor Inter-working Type | Permits the link to interoperate with a Philips SOPHO, Siemens iSDC or Alcatel PBX. For an Alcatel system, the Integrated Digital Access field (above) must be set to DPNSS or ISDN Node. Leave this field blank for any other vendor type. | Blank
Satellite Link Delay | This field permits the link layer to tolerate longer delays between transmissions over satellite. Select "Yes" to allow transmission of frames once every 500 ms until the 64-transmission limit is reached. | No
Slip Rate - Maintenance Limit (slips/24hr.) | Enter the maximum number of slips allowed in a 24-hour period. When the maintenance slip limit is reached a log is produced. The maintenance slip rate must be less than the service slip rate. | 5000
Slip Rate - Service Limit (slips/24hr.) | Enter the maximum number of slips allowed in a 24-hour period. When the service slip limit is exceeded, a maintenance log is generated. | 7000
Alarm Debounce Timer - Service Limit (millisec.) | Enter the minimum length of time an alarm has to be received from the far-end before the link is taken out of service. This is a DS1 parameter. | 500 ms
Voice Encoding | This field is only valid for programming the voice encoding method of the CEPT Formatter II, DS1/T1 Formatter II (Universal T1/E1). Possible values are "Nil" for no change, "ADI" for alternate digit inversion (even bits inverted), "Invert" for all bits inverted, and "Inverted ADI" for odd bits inverted. NOTES Embedded PRI: T1 in North America and E1 in Europe are set to "Nil" by default. However, if you experience noise on the trunks, set Voice Encoding to "Invert" E1 in NA or T1 in Europe must have voice encoding set to "ADI". | Nil
Data Encoding | This field is only valid for programming the data encoding method of the CEPT Formatter II, DS1/T1 Formatter II. Possible values are "Nil" for no change, "ADI" for alternate digit inversion (even bits inverted), "Invert" for all bits inverted, and "Inverted ADI" for odd bits inverted. | Nil
QSIG Private Network Access | Specifies if a QSIG private network is used. | No (indicating ISDN public network)
Digital Link Fault Delay Timer (sec.) | Enter the delay period before alarming digital link faults. The range of values is 0 to 360 seconds (0 to 6 minutes, although the acceptable range is 240 to 360 seconds (4-6 minutes). This is an Italian CAS parameter. | 240
Termination Mode | For Embedded PRI (Dual Framer) only. Select Network Termination (NT), the default, or Line Termination (LT). | NT
Send Malicious Call Indication to PSTN for Tagged Calls | Select "Yes" to automatically send a Malicious Call Indication to the PSTN if the Tag Call feature is invoked for an incoming call via BRI or PRI. The default value is "No". See Malicious Call Trace and Tag Call for more information. | No
Inhibit Sending Mitel Specific Info | Select "Yes" to truncate set up messages transmitted over DPNSS links to switches (such as DMS) that support a maximum message length of 135 octets. The limit is achieved by removing Global Call Reference ID and Network SMDR information, which may cause a reduction in service. | No
T1 Only
B8ZS Zero Code Suppression | T1 only. Specify if the hybrid is to use jammed bit (No) or B8ZS zero code suppression (Yes) on the DS1 link. Zero Code Suppression is a method of reducing timing errors by suppressing all-zero codes and replacing them with another bit pattern. Both ends of the link must specify the same type of zero code suppression. This is a DS1 parameter. | Yes
Operation Mode (CSU/DSX-1) | T1 (on embedded trunking) supports Channel Service Unit (CSU) mode and Digital Signal Cross-Connect Level 1 (DSX-1) mode. If the links connect to an external CSU, set the operation mode to DSX-1. If the links do not connect to an external CSU, set the operation mode to CSU. | DSX-1
CSU Tx Line Build-Out (dB.) | This T1 parameter ensures reliable operation of the network. Select from 0, 7.5, 15, or 22.5 dB. Your carrier can advise you of the correct setting. | 0 dB
DSX-1 line length | This T1 parameter sets the DSX-1 line length. Select from 0-133, 134-266, 267-399, 400-533, or 534-655 feet. | 0-133 feet
Extended Super Frame | Select "Yes" to enable CRC 6 on the T1 card. This is the preferred framing format for DS1 rate terminals, but systems may still use the T1D4 framing format. The Integrated Digital Access must be T1D4. If you select "ISDN Node" in the Integrated Digital Access field, the default changes to "Yes". | No
Inverted D channel (DPNSS only) | This parameter allows you to invert the D channel (signaling channel) on the Dual T1 card links. Select "Yes" to allow communication with other systems. For communication with other manufacturer's system equipment, you may have to set this parameter to "No". NOTE: When this field is changed for a DPNSS trunk, you must reboot the Universal T1. | No
T1-619a Signalling (MLPP Only) | MLPP is not supported by the MiVoice Business sytem. | No
E1 Only
CRC-4 enabled | Select "Yes" to enable CRC-4 checking on an E1 link. If you select "ISDN Node" in the Integrated Digital Access field, the default changes to "Yes". | No
E1 Line Length (Ft.) | This parameter sets the E1 line length. Select from 0-133, 134-266, 267-399, 400-533, or 534-655 feet | 0-133
E1 Impedance (Ohms) | This parameter sets the E1 line impedance. 75 or 120 ohms. | 120 ohms