Nortel DMS-100 Series General Description Manual page 128

5-4 Ringing system maintenance
LM
waveform instead of the transmit voice signal. The line card then sends a
digital representation of the ringing waveform through PCM data to the PM
software. The PM software examines this data to determine the presence of the
ringing voltage. If no ringing voltage is detected (the line card does not send
the digital representation of the ringing signal back to the PM), the
no-ring-current log is generated
LCM
monitor the status of the ringing relay and the ringing voltage applied to the
line. When the ringing relay is operated, the LCM software monitors the status
of the ringing relay. If the ringing relay does not operate, the no-ring-current
log message is output.
Drawer slot occupied
The drawer-slot-occupied log indicates that the ringing generator could not be
accessed. The reason the ringing generator cannot be accessed differs for LM
and LCM. A description of each follows.
LM
generators in the LM. If a previous request results in ringing generator (RG) 1
being applied to the ringing bus in a line drawer, requests for RG 0 must wait
in the awaiting schedule queue until the bus is free. If the wait is greater than
2 s, the ringing request times out and the drawer-slot-occupied log is
generated.
LCM
predetermined threshold, the ringing generator toggles the state of a control
signal to the processor card (NT6X51). The control signal indicates to LCM
software the current threshold on the ringing generator has been exceeded.
When this threshold is exceeded, subsequent ringing requests are denied rather
than queued, and the call is blocked, giving the subscriber the fast busy tone.
Ring slot occupied log
The ring-slot-occupied log indicates that a ringing time slot assigned to ringing
has been given another function, such as ANI/coin or LM maintenance,
resulting in a ringing fault.
Subcycle order failure
The subcycle-order-failure log applies only to the LCM. This log indicates an
incorrect progression of the ringing subcycles has occurred.
Ringing time-out
This log is an information only log and does not indicate a problem. It indicates
a subscriber allowed the called party to ring for a period of time greater than
that specified by office parameter RNG_TMEOUT_NO_OF_SEC. This
parameter is described in Office Parameters Reference Manual. In this
297-1001-131 Standard 06.01 October 2000
When ringing occurs, the line card is instructed to encode the ringing
When ringing occurs, the line cards in the LCM continuously
The ringing buses in the LM can be accessed by both ringing
When the ringing current on the ringing generator exceeds a