General Description - Mitel SX-200 Practices

10
' ONS LINE CARD
1 WARNING 1
Any connectlon of this card to an off premise application, an out of plant appli-
cation, or to any other exposed plant applkation may result in a safety hazard,
and/or defective operation, and/or equipment damage.
General Description
i
IO.1
The On-Premises (ONS) Line Card, part number 9109-010-XXX, interfaces
standard subscriber telephone sets to a PABX in the same building, It contains 12
line circuits and plugs into any digital bay.
The card is 158 mm high x 368 mm long (6.2 in. x 14.5 in.).
There are 13 LEDs on the front face of the card. The top 12 are each connected to a
line circuit and light to show that the circuit is in use. The LED at the bottom of the panel
lights to indicate an alarm (failure) condition.
Facilities
10.2 Each line circuit provides the following facilities:
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Line protection
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Analog-to-Digital / Digital-to-Analog conversion (p-law)
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Line circuit status monitoring
0 Signaling (ringing, message waiting).
Electtical Description
.
10.3 The following description applies to each line circuit.
TIP and Ring are each protected against transients by a 200 volt varistor to ground. A
bridge rectifier provides four protection diodes for the line circuit transistors. The -28
volt line is protected by a 35 volt transorb.
The line circuit performs 2-wire to 4-wire conversion, splitting the signal on the line into
outgoing and incoming speech paths. The analog signal coming from the telephone is
converted to Pulse Code Modulation (PCM); the signal to be sent to the telephone is
converted from PCM to analog audio. These conversions are performed by a Mite1
Codec chip.
9109-096-125-NA Issue1
Revision
0
125 10-l