Small Business Phone System

Line Form (T1 PRI) Overview

Dual port T1 PRI trunk cards are only supported with the IP412 control unit and in Slot A of the IP406 V2 control unit.

Each physical trunk port supports up to 24 channels in T1 mode, 23 channels in PRI and QSIG modes.

• Dialing Complete
  The majority of North-American telephony services use en-bloc dialing. Therefore the use of a ; is recommended at the end of all dialing short codes that use an N. This is also recommended for all dialing where secondary dial tone short codes are being used.   

• AT&T Provider Settings
  For AT&T operation two information elements, TNS (Transit Network Selector) and NSF (Network Specific Facility), are sent in the call setup to the service provider. On IP Office, the values for TNS, NSF and the actual phone number presented to the line are determined by parsing the number dialed through, in sequence, the TNS, Special and Call by Call tabs. These tabs appear when the Provider setting on the Line tab is set to AT&T. Note also that B-channels within the same line can be brought from different service provides. Additionally some B-channels can be used 'call by call', that is, use a different service provider for each call.

Line | Line (T1 PRI)

Settings

• Line Number:
  Allocated by the system.

• Line SubType: Default = PRI
  Set to PRI. If set to T1 see Line Form (T1). If set to ETSI, QSIG A or QSIG B see Line (E1).

• Channel Allocation: Default = 23 -> 1
  The order, 23 to 1 or 1 to 23, in which channels are used.

• Switch Type: Default = NI2
  Options 4ESS, 5ESS, DMS100 and NI2.

• Provider: Default = Local Telco
  Select the PSTN service provider (AT&T, Sprint, WorldCom or Local Telco).

• Prefix: Default = Blank
  Enter the number to prefix to all incoming numbers for callback. This is useful if all users must dial a prefix to access an outside line. The prefix is automatically placed in front of all incoming numbers so that users can dial the number back.

• Test Number:
  Used to remember the external telephone number of this line to assist with loop-back testing. For information only.

• Framing: Default = ESF
  Selects the type of signal framing used (ESF or D4).

• Zero Suppression: Default = B8ZS
  Selects the method of zero suppression used (B8ZS or AMI ZCS).

• Clock Quality: Default = Network
  Sets whether the IP Office takes it clock source for call synchronization and signalling from this line. One line connected to the IP Office should be set to Network. and wherever possible this should be a line connected to the central office exchange. Another line can be set to Fallback but all other lines should be set to Unsuitable.

• CSU Operation
  Tick this field to enable the T1 line to respond to loop-back requests from the line.

• Haul Length: Default = 0-115 feet
  Sets the line length to a specific distance.

• Channel Unit: Default = Foreign Exchange
  This field should be set to match the channel signaling equipment provided by the Central Office. The options are Foreign Exchange, Special Access or Normal.

• CRC Checking: Default = On
  Turns CRC on or off.

• Line Signaling:
  The field can be set to either CPE (Customer Premises Equipment) or CO (Central Office). This field should normally be left at its default of CPE. The setting CO is normally only used in lab back-to-back testing.

• Incoming Routing Digits: Default=0 (present call immediately)
  Sets the number of routing digits expected on incoming calls. This allows the line to present the call to the system once the expected digits have been received rather than waiting for the digits timeout to expire. This field only affects T1 line channels set to E&M Tie, E&M DID, E&M Switched 56K and Direct Inward Dial.

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