P2 and P3 = 4-pin ‘Serial Comm” Connectors. P2 connects via harness 733525 to P8 on the Master Controller or
“daisy-chains” from a previous expansion module; P3 connects to P2’s counterpart on the next expansion
module (if applicable).
l
Pin 1 = TDX (Transmit Data).
l
Pin 2 = COMMON.
l
Pin 3 = RCV (Receive Data).
l
Pin 4 = CODE (not used on the Audio Controller Board).
P4 = 2-pin connector. Phone input. Connects via 733-858 harness to Connector P5 on the Phone Card. Required
only if speakers are to sound phone messages.
l
P4-1 = Talk +.
l
P4-2 = Talk -.
P5 and P13 = 4-pin “Logic/Operating Power” Connectors. P5 connects via 733-525 harness to Connector P2, 3, 4
or 5 on the Master Power Supply, or “daisy-chains” from a previous expansion module; P13 connects to PSs
counterpart on the next expansion module (if applicable).
l
Pin 1 = 8VDC COMMON.
l
Pin 2 = +8VDC.
l
Pin 3 = 24VDC COMMON.
l
Pin 4 = +24VDC.
P6 = 2-pin connector. Harness-connection for local speaker. Connects via 733-576 harness to the Microphone Unit’s
speaker.
l
P6-1 = Speaker + (in parallel with TB3-1).
l
P6-2 = Speaker - (in parallel with TB3-2).
P7, P8 and P9 =3-pin connectors. Audio outputs. Connect via 733-578 harness(es) to Connector P6 on the
appropriate amplifier card.
l
P7 = To Channel 3 Amplifier.
l
P8 = To Channel 2 Amplifier.
l
P9 = To Channel 1 Amplifier.
(if used)
Pl 0, Pll and P12 =1 O-pin connectors. Amplifier status and control. Connect via 733-581 harness(es) to Connector
P7 on the appropriate amplifier card.
l
PlO = To Channel 3 Amplifier.
l
Pll = To Channel 2 Amplifier.
1
(if used)
l
P12 = To Channel 1 Amplifier.
- Pin 1 = OV when amplifier is to output music. Otherwise +24V.
- Pins 2,4,6,8 and 10 = OV COMMON.
- Pin 3 = +24V when Style Z (McCulloh) Relay on amplifier(s) being reset. Otherwise OV.
- Pin 5 = +2OV when backup amplifier in use. Otherwise +6V.
- Pin 7 = +24V when amplifier in trouble. Otherwise OV.
- Pin 9 = +24V when amplifier switched to battery. Otherwise OV.
Jl = Socket for optional Message Memory Assembly.
J2 = Socket for optional Message Expansion Assembly. Used for second channel, VTG 2.
J3 = Socket for optional Backup VTG Assembly.
NOTE:
U42 is the location of 740-681 Chipset No. 1. If the 562-898 Message Memory Board is installed in Audio
Controller Board Socket Jl , the U42 position is empty.
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