AT&T DS1/DMi/ISDN-PRI manual Criteria for Switching Back to the Primary

7-60	ADMINISTRATION OPTIONS AND REQUIREMENTS — GENERIC 2
	Criteria for Switching Back to the Primary
	At the end of the 1-hour interval, the slip count is analyzed. If the primary slip
	count is less than 2, then a switch back to the primary is made. Also, if the primary
	has a slip count of 44 or less and if the secondary and 50% of those DS1s that are
	enabled for slip enable have reached their maximum slip count of 88, then a switch
	back to the primary is made.
Field 11	Offers the options external loop not available (0) or external loop available (1).
	The external loop available option should only be selected when demand diagnostic
	maintenance is done and then only after the interface has been busied out. This
	option is used with procedure 620, Test 2 to extend the range of the test to include
	the network channel-terminating equipment (NCTE) and the connecting facility
	(any external equipment to the point of the DS1 loop around). The test requires
	that either the colocated or the distant NCTE be physically optioned for loopback
	mode.
	The external loop available option should only be used for the duration of the test.
Field 12	Specifies whether (1) or not (0) the associated T1-span is used as an incoming
	synchronization source to the switch. The network synchronization diagram should
	show those transmission facilities that are used for synchronization. Each switch
	permits a maximum of two interfaces (one primary and one secondary) to be
	translated (1) in field 12. However, there is no requirement to have both.
	For the case where Generic 2 is the master timing server, neither primary or
	secondary is administered.
	Each Generic 2 that is equipped with a DS1 will also contain a TN463
	synchronization clock (SC). For single-module systems, the SC is located in the
	module control carrier along with the TN460 module clock. For multimodule
	systems, the SC is located in the TMS carrier. The SC should have previously been
	assigned in procedure 250.