Accessory Connector Pin Functions
Radio Installation
1-13
11
Flat_RX_Audio
(NPD Data In)
The signal routed to this pin is controlled by ASFIC and gives continuous discrim-
inator audio. For discriminator audio, the nominal ouput level is 330mVRMS for
60% deviation. The impedance is 600ohms.
12
Programmable
Output (CTS)
This digital output function depends on dealer programming. The DPS details
which functions may be assigned to this pin by the codeplug.
(See Notes 2).
13
SW_B+ sense
(Analogue
Ground)
This voltage is available when the radio is switched on.
The current limiting resistor R0425 default is 22 ohms.
(See Caution 2)
14
Hook (Clear)
This hook line is in parallel to the hook line of the control head microphone con-
nector. This port reads ‘0’ when the microphone is on-hook and ‘1’ when the
microphone is off-hook. It is assumed that the hook is a mechanical switch, so
the software will always debounce this input.
Also available on the microphone connector pin 3.
15
RSSI
This is an analog output which indicates the strength of the received signal.
16
External
S
Positive output of radio’s audio PA (see Pin 1).
Note 1 :
Digital Input
4.7 k
Ω
Internal Pull Up Resistor to +5V.
Maximum Input Voltage accepted as Low = 0.6V
Minimum Input Voltage accepted as High = 3.0V
Note 2 :
Digital Output
4.7k
Ω
Internal Pull Up Resistor to +5V
Maximum Current when Output Low = 10mA
Maximum Voltage when Output Low = 0.5V @ 10mA
Note 3 :
High Current Digital Output
4.7k
Ω
Internal Pull Up Resistor to cont
Maximum Current when Output Low = 200mA
Maximum Voltage when Output Low = 1.7V @200mA
Note 4:
Low current Digita; Output
No internal Pull Up resistor
Maximum Current when Output Low = 1mA
Maximum Voltage when Output Low = 1V @ 1mA
Note 5:
Digital Input
3.3k
Ω
Internal Pull Up Resistor to cont
Should be connected to an open drain or open collector
Pin
Function
Description
