Tifn Maintenance Actions - Northern Telecom DMS-100 Series Manual

Maintenance principles 2-7

TIFN maintenance actions

Maintenance operations can be performed on the Telephony Interface Node
(TIFN), the 68K card, the T1 card, T1 spans, T1 channels, and SMDI links.
Normally, a maintenance action performed to a higher entity causes a ripple
effect for lower entities. For example, if the T1 spans are in the inservice
standby state, disabling a T1 card causes all four T1 spans to be switched to
the alternate T1 card. Likewise, disabling a T1 span causes all 24 channels
to be switched to the alternate T1 card. Disabling one channel causes only
one channel to be disabled.
A fault in the 68K card of a TIFN can cause all four T1 spans and SMDI
links to switch to the redundant TIFN. A fault to a single T1 span causes
that single span to switch to the redundant TIFN.
The only reason to disable a TIFN, or one of its associated cards, is to
replace the card in question or to run out-of-service diagnostics against a
suspected fault.
In some cases, surviving T1 spans of a TIFN are disabled, switching the
span to the redundant TIFN to allow the TIFN with a failed span to be
replaced.
DMS VoiceMail Trouble-locating and alarm-clearing procedures SPM 02