D connector standard 15-09-04 For radio interconnection


Use DB9 connectors as follows:
Male on receiver
Female on Transmiter

Notes:
1.All connectors to be assembled flying lead to allow compatability
2. Locking nuts should be fitted to the female only
3. 5 or 8 core shielded data cable is suggested for use depending on the implimentation

RX (DB9 MALE)	TX use (DB9 Female)	9 pin #
Power Earth	Power Earth	1
RX aud (demphed)*#	TX aud (to be premph/limited)*	2
CD open collector (GND=carrier detected)	PTT= GND to tx (pulled up in tx)	3
		4
+13.6V Controller currents	+13.6V Controller currents  (power from transmitter via 0.5A poly switch)	5
Shield	Shield	6
Rx audio RAW*#	TX audio RAW*%	7
Signal Strength 0=low +5=high	Power Control, 0=low +5=high	8
		9

* Audio is 0dBm (775mV into 600 ohms)  corresponding to max dev, i.e. premphed, 5kHz dev, 300Hz mod tone. Output source impedance should be 100 Ohms and 47uF in series from an opamp.  Receiver input should be terminated with 620 ohms and capacitively coupled with 1uF or 2.2uF into a bridging load.

#   A +5 to +12V potential coupled to this line via the termination resistor in the controller is to disable muting of this line.

% Caution this transmit line is NOT limited before hitting the modulator and should only be used for signalling.  The only exception for this is when operating a voting system, and the adjacent channels are not in use.

Please see the following suggested circuit configurations for driving these lines:
TX limiter and premphasis circuits
TX channel filter, for ham use only, or for use on commercial channels (fits between the output of the previous circuit and the modulator)

The Ham use only channel filter has a much extended cut off frequency that will make the audio much nicer but will result in a slight excersion beyond the nominal chanel bandwidth.

The Commercial channels channel filter has been designed to AS4295-1995 and if you do use this filter or any other modifications that I have set out here on this page on commercial channels it is YOUR responsability to ensure that you meet all the ACA mandated specifications of transmission.

RX circuit


You will note that these circuits are not complete and not pretty.  I just have not had time ot fully CAD capture them and show all the combinations.  You will also find the CD and PTT circuits for interfacing to various radios are not complete, again I need to find time to compile my notes into a distrutable form suitable for posting on this site.  I will do this as I can, so please check back to see if I have improved things.