Avaya Business Telephone Systems

Line | BRI Overview

Point-to-Point or Multipoint
BRI lines can be used in either Point-to-Point or Point-to-Multipoint mode. Point-to-Point lines are used when only one device terminates a line in a customer's office. Point-to-Multipoint lines are used when more than one device may be used on the line at the customer's premises. There are major benefits in using Point-to-Point lines: -

1. The exchange knows when the line/terminal equipment is down/dead, thus it will not offer calls down that line. If the lines are Point-to-Multipoint, calls are always offered down the line and fail if there is no response from the terminal equipment. So if you have two Point-to-Multipoint lines and one is faulty 50% of incoming calls fail.

2. You get a green LED on the Control Unit when the line is connected. With Point-to-Multipoint lines some exchanges will drop layer 1/2 signals when the line is idle for a period.

3. The timing clock is locked to the exchange. If layer 1/2 signals disappear on a line then the Control Unit will switch to another line, however this may result in some audible click when the switchover occurs.

The IP Office's default Terminal Equipment Identifier (TEI) will normally allow it to work on Point-to-Point or Point-to-Multipoint lines. However if you intend to connect multiple devices simultaneously to an BRI line, then the TEI should be set to 127. With a TEI of 127, the IP Office control unit will ask the exchange to allocate a TEI for operation.

Note: When connected to some manufactures equipment, which provides an S0 interface (BRI), a defaulted Control Unit will not bring up the ISDN line. Configuring the Control Unit to a TEI of 127 for that line will usually resolve this.

Line | BRI Line

Settings

• Line Number
  This parameter is not configurable; it is allocated by the system.

• Line Sub Type:
  Select to match the particular line type provided by the line provider. BRI supports ETSI and AusTS013.

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

• Prefix: Default = Blank.
  The prefix is used in the following ways:

• • For incoming calls, the ISDN messaging tags indicates the call type (National, International or Unknown). If the call type is unknown, then the number in the Prefix field is added to the ICLID.
  • For outgoing calls, when the number presented to the line for dialling includes the prefix, the prefix is stripped.
• National Prefix: Default = 0
  This indicates the digits to be prefixed to a incoming national call. When a number is presented from ISDN as a "national number" this prefix is added. For example 1923000000 is converted to 01923000000.

• International Prefix: Default = 00
  This indicates the digits to be prefixed to an incoming international call. When a number is presented from ISDN as an "international number" this prefix is added. For example 441923000000 is converted to 00441923000000.

• TEI: Default = 0
  The Terminal Equipment Identifier. Used to identify each device connected to a particular ISDN line. For Point-to-Point lines this is 0. It can also be 0 on a Point to Multipoint line, however if multiple devices are sharing a Point-to-Multipoint line it should be set to 127 which results in the exchange allocating the TEI's to be used.

• Number of Channels:Default = 2. Range = 0 to 2.
  Defines the number of operational channels that are available on this line.

• Outgoing Channels: Default = 2. Range = 0 to 2.
  This defines the number of channels available, on this line, for outgoing calls. This should normally be the same as Number of Channels field, but can be reduced to ensure incoming calls cannot be blocked by outgoing calls.

• Voice Channels: Default = 2. Range = 0 to 2.
  The number of channels available for voice use.

• Data Channels: Default = 2. Range = 0 to 2.
  The number of channels available for data use. If left blank, the value is 0.

• 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.  

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