Maintenance Page 327 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
When the DSP recovers , al l th e as so ci at ed ch an n el s ar e pu t int o the “IDLE”
state. “REStart” mes sages for all chann els are sent to the Me ridian 1 to reset
the trunks to the “IDLE” st ate. The leader car d is infor med an d in coming cal ls
can be assigned to those channels.
Card failure
If following a reboot, the ITG card displays a code in the form of F:xx on t he
faceplate Maintenance display, this indicates an unrecoverable hardware
failure. The card will not register with the Meridian 1.
Remove the card for two to three seconds and then re - seat it in the IPE shelf.
If the failure continues, replace the card.
DCH failure
This section covers the following three t ypes of DCH failure which can affec t
the ITG card:
• DCH li nk failure (DCH releases)
• PC card failure
• DCH card failure
When the DCH fails (with no backup DCH):
• E stablished calls are maintained.
• Transient calls are dropped.
• No new incoming calls are assigned to trunks associated with that DCH.
• Outgoing calls are blocked from occurring by the associated Follower
cards forcing their trunks to a busy state.
• Whe n the fa r-end user releases an established call, t he system uses SSD
messaging to Meridian 1 to inform the core the call is released.
• Whe n the ne ar end user releases an established call, the Meridian 1
informs the Follower through SSD messages.
• ISDN features across the IP will not work.