Nortel DMS-100 Series General Description Manual page 84

3-16 Ringing in Series II peripherals
NT6X54 bus interface
The NT6X54 bus interface card (BIC) multiplexes and demultiplexes PCM
samples and control messages to and from the LCM line cards over the
32-channel digroups. It also contains relays that switch ringing or ANI/coin
voltages to the line cards. Under the direction of the LCM processor card, the
bus interface card ringing relays connect the ringing generator output to the
appropriate line card ringing bus. The BIC also provides the capability to
reverse the ring bus within the drawer.
NT6X52 digroup control
The digroup control card instructs the line card, through PCM codes, to
operate or release its ringing relay. This operation is described next.
Line card functional description
The line circuit card provides voice and signaling interfacing between the
subscriber line and the DMS-100. In the ringing system, the line card contains
a ringing relay that connects the subscriber line to the ringing bus as illustrated
in the following figure. Under the direction of the LCM processor card, the line
circuit card achieves ringing by connecting the subscriber line to the ringing
bus. The ringing relay is alternately operated and released to establish the
proper ringing cadence (ringing and silence periods) on the subscriber line.
Figure 3-5 Line card bias circuit
The LCM uses the following line cards:
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•
•
•
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297-1001-131 Standard 06.01 October 2000
R R i i n n g g i i n n g g rre e l l a a y y
Talkbattery
Ring bus (R)
Battery return
Ring bus (T)
NT6X17 - Type A
NT6X18 - Type B (needs NT6X23 if +48 V option is used)
NT6X19 - Message waiting (needs NT6X20 -150V power supply)
NT6X21 - P-phone
NT6X71 - Data
200 Ohms
200 Ohms
Ring
1microfarad
Tip