Electrical Description; Operation - Mitel SX-200 Practices

Circuit Card Descriptions
Electrical Description
13.3 Each Digital Network Interface Circuit (DNIC) connects a DATASET,
SUPERCONSOLE 1000 Attendant Console, SUPERSET DSS Module,
SUPERSET 3 DN, SUPERSET 4 DN, SUPERSET 401, SUPERSET 410,
SUPERSET 420, or a SUPERSET 430 telephone to the common circuitry on the
DLC card (and then to the PABX). The common circuitry will be described first,
followed by a description of one DNIC.
The common circuitry contains a High-level Data Link Controller (HDLC) which
controls the D channel communication between each DNIC and the Main Control Card
(MCC) within the PABX. This data is passed over one-half of a link to the MCC. The
'Bl and B2 channels from the DNlCs are multiplexed onto one link between the DLC
and the MCC. The common circuitry includes phase-lock loop circuitry to keep the
DNlCs in synchronization with the system clock, as well as circuits which prevent the
DLC from disrupting the backplane when a card is inserted or removed. The DLC line
circuits are arranged in three groups of four; at power-up, each group can be
separately sequenced. There are 12 Digital Netvvork Interface Circuits (DNIC) on the
DLC card, each connected to a separate tip-ring pair.
DN IC Description
13.4 Each DNIC connects via its tip-ring pair to a proprietary telephone, or a proprietary
telephone with a data cartridge, or a DATASET which also contains a DNIC. The
DNlCs communicate with each other over the twisted pair at 160 Kbit/s (two 64 Kb/s
Bi and B2 channels and a D channel). Since the DNIC is a proprietary integrated
circuit, each device connected to a Digital Line Card DNIC tip-ring pair must also
contain a DNIC. The two DNlCs communicate data plus voice simultaneously in full
duplex over the single twisted pair between them. The twisted pair also carries the
power required by the SUPERCONSOLE 1000, SUPERSET DSS Module,
SUPERSET 3 DN, SUPERSET 4 DN, SUPERSET 401, SUPERSET 410,
SUPERSET420, or the SUPERSET telephone from the DNIC on the DLC. The
DATASET is powered from a separate AC power supply.
-Operation
13.5 The Digital Line Card communicates with a DNlC-equipped device using digital
transmission techniques; a voice channel, a data channel, and a control channel. It
allows simultaneous transmission of voice and data over a single twisted pair of
wires. When the DLC is connected to SUPERSET 3 DN or SUPERSET 4 DN,
telephones, each telephone may be ordered with a Data Cartridge which can be
connected to a personal computer, or similar data device. When the DLC is
connected to SUPERSET 4 10, SUPERSET 420, or SUPERSET 430 telephones,
each telephone may be connected to a MLhk Data Module which can be connected
to a personal computer, or similar data device. The telephone's voice operation and
the data device's data operation can both function concurrently.
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