Meridian America 21 Manual De Usuario

The following features are provided:

l 

 balanced terminating impedance

 

 

 

l 

-48 V through a battery feed resistance and ground

l 

supervise the loop current to determine on-hook/off-hook status

l 

ringing current to the loop

l 

isolation of foreign potentials on the loop from the transmission and
signaling circuit

l 

conversion from a   to a 4-wire transmission path

l 

analog-to-digital and digital-to-analog conversion of transmission

signals

l 

common multiplexing’ circuit to interface with the peripheral bus

signaling channel

.

l 

retime the digital signals received from the peripheral bus

l 

decode address information received from the peripheral bus to

enable individual line circuits during selected time slots

l 

control the disconnection timing of ringing current to the loops to

avoid switching during current peaks.

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4.02 The various special versions of the 

 line pack have

additional features as follows:

l 

serve lines up to a maximum loop resistance of 1400 

l 

serve Dataphone sets

l 

have line-to-line insertion loss of 1 

l 

provides connection of -150 V in a steady or 1 Hz flash rate to
activate the Message Waiting lamp on the telephone

l 

provides for one Message Waiting lamp per line

l 

maintain all Message Waiting lamps off and do not allow phones to
ring during power-up sequence.

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