Nortel DMS-100 Series General Description Manual page 19

applies power ringing at the start of the next available ringing cycle. If power
ringing can not be applied during the first time slot of a ringing cycle, the
DMS-100 switch will try to schedule power ringing during the first time slot
of the next ringing cycle. This can cause delays in power ringing of up to 6 s
in LCMs and up to 8 s in line modules (LM). To reduce these delays, an
immediate ringing mode is available.
In the immediate ringing mode, the DMS-100 switch applies power ringing
during the next available time slot of the ringing portion of the ringing cycle.
If power ringing cannot be applied during the first time slot of the ringing
portion of a ringing cycle, the DMS-100 switch will try to schedule power
ringing during the next time slot of the ringing portion of the same ringing
cycle. The DMS-100 switch attempts to schedule power ringing during each
time slot of the ringing portion of a ringing cycle until power ringing can be
applied, or the ringing portion of the ringing cycle expires. If power ringing
can not be applied during this ringing cycle, the DMS-100 will try the next
ringing cycle.
Immediate ringing is enabled or disabled by office parameter
IMMEDIATE_RING_ENABLE in table OFCENG.
Note: When changing the office parameter
IMMEDIATE_RING_ENABLE in table OFCENG to Y, consideration must
be given to the value datafilled for office parameter
ALLOW_RINGING_ON_TIP_SIDE. When this office parameter is set to
Y, a considerable amount of ring slots are reserved for tip side ringing
functionality. This may delay the next available time slot in the ringing
portion of the ring cycle. For more information on office parameter
ALLOW_RINGING_ON_TIP_SIDE, refer to Office Parameters Reference
Manual.
An illustration of normal and immediate ringing for a 1FR (1 flat rate is a
standard line option) is shown in the following figure. This illustration is not
specific to any ringing type. It illustrates the differences in normal and
immediate ringing on a 1FR line when time slot 0 of the ringing cycle is
unavailable.
DMS-100 Family DMS-100 Ringing System BASE15 and up
DMS-100 ringing overview 1-3