Meridian America 61 Benutzerhandbuch

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PRACTICE 553-2201-183
4. CHARACTERISTICS
FUNCTIONAL
Common Features
4.01 
The following features are provided:
 balanced terminating impedance
Unique Features
 
 
 
-48 V through a battery feed resistance and ground
supervise the loop current to determine on-hook/off-hook status
ringing current to the loop
isolation of foreign potentials on the loop from the transmission and
signaling circuit
conversion from a   to a 4-wire transmission path
analog-to-digital and digital-to-analog conversion of transmission
signals
common multiplexing’ circuit to interface with the peripheral bus
signaling channel
.
retime the digital signals received from the peripheral bus
decode address information received from the peripheral bus to
enable individual line circuits during selected time slots
control the disconnection timing of ringing current to the loops to
avoid switching during current peaks.
- -
4.02 The various special versions of the 
 line pack have
additional features as follows:
4.03 
 and QPC292 OPX Line packs:
serve lines up to a maximum loop resistance of 1400 
serve Dataphone sets
have line-to-line insertion loss of 1 
4.04 QPC494 and QPC558 Message Waiting Line packs:
provides connection of -150 V in a steady or 1 Hz flash rate to
activate the Message Waiting lamp on the telephone
provides for one Message Waiting lamp per line
maintain all Message Waiting lamps off and do not allow phones to
ring during power-up sequence.
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