Specifications

series with analog inputs is required to
block the 1.8 volts DC present at this pin.
Frequency
Response:
Flat within +1/-3 dB, 5 Hz to 2.4 kHz.
Note: The input is DC coupled to allow
for proper switching of both TTL/CMOS
and RS-232 logic signals, but capacitive
coupling is used later in the audio chain
limiting the frequency response to 5 Hz
on the low end.
Digital bit streams are limited to 4800
baud maximum and should not have any
continuous string of 0’s or 1’s for longer
than 100 ms.
Polarity: Positive; the most positive input voltage
produces the highest carrier frequency.
Pin: 12
Name: REMOTE AUDIO B
Type: Analog Output
Description: Normally not connected.
Pin Number: 13
Name: EXT DCS/CTCSS
Type: Analog Input
Description: External input for either DCS (CDCSS)
or CTCSS. The signal at this input is en-
abled through the programming software.
Impedance: 10 kohm.
Level: An input level between 250 mv and 750
mv RMS, depending upon the setting of
R581 (EXTERNAL CTCSS DEV. ADJ.),
on the main board is required to produce
700 Hz deviation of a 100 Hz tone.
Frequency
Response:
Within +1/-3 dB from 10 Hz to 300 Hz.
Polarity: Negative; A positive input voltage change
will produce a negative frequency change.
Pin Number: 14
Name: INTRCNT. TX AUD
Type: Analog Input
Description: This pre-emphasized audio input modu-
lates the transmit carrier when the IN-
TERCONNECT PTT is taken to its active
state and when no higher priority PTT has
been enabled.
Impedance: 600 ohms nominal, unbalanced.
Level: Depending upon the setting of R548 (IN-
TERCONNECT AUDIO) on the main
board, between 25 mv and 250 mv RMS
nominal at 1 kHz will produce ± 3 kHz
deviation.
Frequency
Response:
From 300 Hz to 3 kHz within +1/-3 dB of
a 6 dB/octave pre-emphasis curve.
Pin Number: 15
Name: INTRCNT. CONT
Type: Digital Output
Description: This output goes to logic low state when
the receiver properly decodes User Tone
16 as programmed.
Level: Active low CMOS output. Logic low
level is 0 to 0.4 volts at up to a sink cur-
rent of 6 mA. Logic high level is 3.7 to
5.0 volts when sourcing up to 6 mA.
PTT PRIORITIES AND TX AUDIO
DETAILS
The PTT function has 5 priority levels. The TX audio in-
put associated with each priority level (source) is detailed in
Table 1 on the next page.
AE/LZB 119 1882 R1B
18