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Primary Rate Interface (PRI) and T1 Feature

Description

Timers and Counters

This option sets the timer and counter thresholds. The factory settings for thresholds are standard and rarely need to be changed. (See At a Glance for factory settings and valid ranges.) When no response is received from the network before the duration of the timer setting, the communications system takes appropriate corrective action.

	CAUTION:
	After initial installation, these timers rarely, if ever, should be changed.

The timers and counters are as follows:

• T200 Timer. Times the delay in link layer acknowledgment of a message sent from the communications system to the network over a D-channel.
  
  
• T203 Timer. Times the period of time between each exchange of messages between the system and the network on the D-channel.
  
  
• N200 Counter. Counts the number of times the communications system has transmitted a message on a D-channel because no link layer acknowledgment is received from the network.
  
  
• N201 Counter. Counts the maximum number of layer 3 octets the system can send or receive in a single D-channel message.
  
  
• K Counter. Counts the number of layer 3 unacknowledged messages sent from the communications system to the network on a D-channel.
  
  
• T303 Timer. Times the delay in network response when the system sends a setup message to initiate an outgoing call.
  
  
• T305 Timer. Times the delay in network response when the communications system sends a disconnect message to clear a call.
  
  
• T308 Timer. Times the delay in network response when the communications system sends a release message to clear a call.
  
  
• T309 Timer. Times the duration of a D-channel data link failure (a loss of signaling for the entire PRI connection).
  
  
• T310 Timer. Times the network delay following the receipt of a call-proceeding message on an outgoing call.
  
  
• T313 Timer. Times the delay in network response when the communications system sends a connect message that indicates the completion of an incoming call.
  
  
• T316 Timer. Times the delay in network response when the communications system sends a restart message to clear a B-channel.
  

Topics
	Description
	Called Party Nunber (CdPN) Calling Party Number (CPN) Lines / Trunks PRI T1 DS1 Facility Options Type of Service Framing Format Line Coding Channel Service Unit   Line Compensation Signaling Mode Tandem PRI Trunks Tandem PRI Trunk Programming PRI Programnming Options PRI Programnming Options - PRI Telephone Number PRI Programnming Options - Network Services Supported PRI Programnming Options - Copy Telephone Number to Send PRI Programnming Options - Telephone Number to Send PRI Programnming Options - Test Telephone Number   PRI Programnming Options - Timers and Counters PRI Programnming Options - Terminal Equipment Identifier (TEI) PRI Call Processing Incoming Calls Outgoing Calls Network Selection Table Call-by-Call Services Table Station Identification - Automatic Number Identification T1 Programming Options T1 Programming Options - T1 Tie Trunk Connections T1 Programming Options - T1 Routing by Dial Plan System-wide Programming Options - Clock Synchronization System-wide Programming Options - Clock Switching
	At a Glance
	Considerations & Constraints
	Incoming Calls Outgoing Calls
	System Programming
	Mode Differences
	Feature Interactions