Interfacing the Delta

By Dave Karr, KA9FUR

Radio Connector Pin by Pin summary
1 FB1 Wht/Brn BCD channel selector, A.  Pulled up to +5V through a 10k resistor.
2 FB2 Wht/Red BCD channel selector, B.  Pulled up to +5V through a 10k resistor.
3 FB3 Wht/Blu BCD channel selector, C.  Pulled up to +5V through a 10k resistor.
4 FB4 Wht/Vio BCD channel selector, D.  Pulled up to +5V through a 10k resistor.
5 Mic Lo Shield(9) Microphone input ground/shield connection
6 Vol/Sq. Lo Shield(7,8,15) Volume Squelch ground/shield connection
7 Vol/Sq. Hi Grn Volume Squelch output (low impedance non-demphasized, non-squelched audio)
8 Vol Arm Blu Audio amplifier input from external volume control
9 Mic Hi Brn Microphone input
10 *CG Disable Wht/Grn Ground this line to disable Channel Guard and mute received audio based on carrier squelch only.  Also used as serial control line during programming.
11 *PTT Wht Push to talk.  Ground to Transmit
12 CAS Vio Channel Activity indicator.  Follows Carrier Squelch action only regardless of radio programming.  0 Volts when squelched, 9 volts (via a 10k pullup) when un-squelched.
13 *CCT/*SQ Disable Org/Blu Grounding this pin enables the audio amplifier but does not force open the received audio gate.  Used to enable the speaker audio amplifier to generate an alert tone when the CCT timer expires.
14 Cont. A- Shield(17) Negative power supply output.  Leave this unconnected.
15 Sq. Arm/*SQ Disable Grey With J605 shunted between pins 2 & 3 this is the squelch arm input.  With J605 shunted between pins 1 & 2, when this pin is grounded, all squelch action is overriden and received audio is passed to the speaker.
16 Ignition A+ Red (small) Positive power supply connection.  Essentially a logic input to the radio but needs A+ for radio to work.
17 Alert Tone Yel/Grn Input to the audio amplifier for time out timer alert tone.  This pin also has squelched volume squelch high audio on it, but also be aware that it is also DC Biased to 4.5 Volts so AC couple to this if you want to use it for something.
18 Speaker 1 Green (16ga.) One side of the speaker
19 A+ Yellow (16ga.) Positive power supply connection.  This provides all power to the radio except for the RF Power Amplifier
20 Speaker 2 Brown (16ga.) The other side of the speaker.
21 A- Black (16ga.) Negative power supply connection
22 N/C
23 N/C
24 N/C
25 N/C
26 Spare, HL1 White Option specific.  DATA IN for some radios.
27 Spare, HL2 Orange Option specific.
28 Spare, HL3 Shield (26) Option specific.
29 *Store Wht/Org Used for radio programming.  Grounding this line will cause the EEPROM to save data to non-volitale memory.
30 FB5/Mode A,*B Wht/Grey Used to select between two EEPROM banks.  Also used as serial data line for radio programming.
31 Spare, HL 6 Yel/Vio Option specific.
32 Advance Change, HL7 Yel/Blk Used by scan heads to advance channel.  Also used as serial data clock line for radio programming.
33 Spare, HL8 Org/Grn Option specific.
34 *RX Mute, HL9 Yel/Blu Ground to mute receiver audio...  Side benefit is that it can be used as a Channel Guard decode indicate output.  Open Collector output with a 10k pullup to +9 Volts.  Grounded by Q721 when no Channel Guard tone is detected.
35 N/C
36 *RESET Org/Red Used for radio programming.  Grounding this pin will put the microprocessor into RESET.
37 TX A+ Red (8 ga.) High current positive power supply connection.  Provides power to RF Power Amplifier only.
38 TX A- Blk (8 ga.) High current negative power supply connection.  Provides power to RF Power Amplifier only.


Interfacing Notes

- For Receive applications -

  • Unsquelched, low impedance, discriminator (flat) audio output is found on pin 7.  Ground/Sheild to pin 6 if needed.
  • CAS (carrier squelch indicate) can be found on pin 12.
  • Channel Guard Decode indicate can be found on pin 34.
  • Use internal squelch control by removing shunt on J605, OR shunt J605 2&3 and install a 10k pot between Pin 7 and 6 with the wiper connected to pin 15 to act as a squelch control.

  • For a combined Channel Guard Decode and Carrier Squelch logic output there are a few different choices: