Avaya 03-300430 User Manual

The ISDN specification defines two service state categories for B channels as listed in 

Service states

In-Service (INS)

B channel is in normal 

operating state

Active

A call is connected over 

the B channel.

Idle

There is no call on the 

B channel.

Out-of-Service/

Far-End (OOS/FE)

The switch has not successfully negotiated B-channel connection as 

of yet.  Calls cannot be placed or received.
When you first administer a B channel, the switch initializes the 

B channel to this state while it tries to negotiate a connection to the far 

end.  If the request times out with no response from the far end, the 

switch leaves the B channel in the OOS/FE state.

Out-of-Service/

Near-End (OOS/NE)

The NPE Crosstalk test has failed, or the trunk is busied out.  Calls 

cannot be placed or received.

Maintenance/

Far-End (MTC/FE)

A request has timed out with no response from the far end after 

signaling is in place and B channels are in service.  Calls can be 

received but not placed, and stable calls are unaffected.

Maintenance/

Near-End (MTC/NE)

The signaling channel (ISDN-LNK) has been busied out, possibly after 

test trunk grp#/mem# long.  Calls cannot be placed or received, 

but stable calls are unaffected.

Pending states

The switch is waiting for a reply from the far end.  Pending service 

states remain in effect until the near end receives a response or times 

out.

Pending-in-Service

The near end is waiting for a response to a transition-to-service 

request.

Pending-

Maintenance

The near end is waiting for a transition-to-maintenance-service 

request (US and other country-protocol-1 systems).