Service manual

21
Functional Description
DCB, DCFCB and DCFCTB Models
TP1
Two-Tone Decoder, HighPass Filter Enable
Goes high when processor is decoding a tone > 2100 Hz
TP2
Receive audio to Two-Tone Decoder
Audio at last stage before two-tone comparator, 1 to 3 Vp-p.
TP3
Transmit audio
0.1 to 3 Vp-p.
TP4
Receive audio from Two-Tone Decoder to processor
Audio after two-tone comparator, square waves to processor, 0 to
5 Vp-p.
TP5
Voltage at 48 Volt Battery Input
0 – 70 Volts = 0 – 5 Volts
TP6
Voltage at 12 Volt Battery Input
0 – 20 Volts = 0 – 5 Volts
TP7
Two-Tone Decoder, LowPass Filter Enable
Goes high when processor is decoding a tone < 400 Hz
TP8
Receive audio level set
External transceiver receive audio set to 1Vpp using R48
TP9
RX Data
Receive data from digital modem IC, 0 to 5 Volts.
TP10
DTMF Decoder STD
Goes low whenever a DTMF digit is being decoded.
TP11
8 Volt Regulated power supply
TP12
5 Volt Regulated power supply
TP13
Incoming unregulated 17 Volt power supply