Seeking Technical Information for Remote Control & Integration of Kenwood NX-820

[LynxVortex]

Hello everyone,

I recently purchased a Kenwood NX-820 mobile radio and I’m looking for technical guidance on integrating and remotely controlling the device. My goal is to extend its capabilities for operational efficiency while ensuring full compliance with Kenwood’s licensing and software requirements.

I already have the KPG-141D software for programming, but I have a few technical questions:

• Pin Assignments: Which pins handle data transmission, audio input/output, PTT, and power supply?
• Documentation: Are there any official or community-sourced pinout schematics available?
• Communication Parameters: What are the baud rate, data bits, stop bits, and error-checking mechanisms used?
• RS-232 Connectivity: Can I interface with the radio using a standard RS-232-to-USB adapter via the DB-15 accessory port on back?
• Remote Commands: Does Kenwood provide any API or official documentation for remote control?
• Third-Party Solutions: Has anyone successfully integrated third-party control applications or custom hardware interfaces?

My intention is not to bypass any licensing restrictions or unlawfully access proprietary software. I am simply looking for legal and supported methods to integrate the NX-820 into an advanced communication system.

If anyone has experience with integrating Kenwood NX-series radios, I would greatly appreciate your insights!

Thanks in advance!

 

[MTS2000des]

Might help if you told us what exactly you are wanting to accomplish: are you trying to integrate it as a donor radio in a dispatch console (like an Avtec Scout Outpost?), a radio gateway like an ICRI or ACU? Or a crossband repeater?

 

[mmckenna]

You want the Kenwood In Depth manuals for that model radio. It'll have all the information you need.
But, you might have better luck with the NX-800, as it has more pin access capability than the 820.

I've got several NX-900's integrated into a dispatch console using interface adapters.

 

[LynxVortex]

Might help if you told us what exactly you are wanting to accomplish: are you trying to integrate it as a donor radio in a dispatch console (like an Avtec Scout Outpost?), a radio gateway like an ICRI or ACU? Or a crossband repeater?

Hi, thanks for asking! I’m planning to integrate the NX-820 primarily as a donor radio within a dispatch console environment. My goal is to develop a virtual control head that allows remote control and monitoring (including telemetry such as RSSI, voltage, and audio logging), essentially replicating the functionality of a directly connected radio in a centralized dispatch setup similar in spirit to systems like the Avtec Scout Outpost . I’m still refining the overall architecture, so any insights on best practices or similar implementations would be greatly appreciated.

You want the Kenwood In Depth manuals for that model radio. It'll have all the information you need.
But, you might have better luck with the NX-800, as it has more pin access capability than the 820.

I've got several NX-900's integrated into a dispatch console using interface adapters.

Thank you for the suggestion! I’m aware that the NX-820 might offer more limited pin access compared to models like the NX-800, and I’ve seen that some have had success with the NX-900 in dispatch console integrations using interface adapters. However, since I’ve already acquired the NX-820, my immediate focus is on exploring its integration possibilities. Any additional documentation or tips—especially from those who’ve managed similar setups would be very helpful. If significant limitations arise, I may consider alternative models down the line.

 

[MTS2000des]

As mentioned, you'll be better off sourcing an NX800. These are pretty straightforward interfacing to things like the Avtec outposts.

 

[LynxVortex]

As mentioned, you'll be better off sourcing an NX800. These are pretty straightforward interfacing to things like the Avtec outposts.

NX-800 is generally recommended due to its easier interfacing, but I’m curious if I had access to an NX-800, what specific advantages or simpler modifications would it offer for a project like mine? I’m aiming to build a virtual control head for remote control and monitoring (including telemetry like RSSI, voltage, and audio logging) within a dispatch console environment.
On the other hand, for the NX-820 that I currently have, is it feasible to utilize the rear accessory connector (the DB-15 port) to achieve these functionalities directly without involving additional LAN/WAN layers?

 

[ramal121]

The NX-800 is easier to set up but the NX-820 can also be used with considerations. First tx and rx audio needs to be changed to filtered audio and the serial data needs to be changed from TTL to RS-232 on the rear DB15 connector. These are mods internal to the radio.

Second is a big stumbling block. You need the command structure for remote control via the serial line. Kenwood holds this information pretty close to their chest. Usually only released to authorized developers. If you can wrangle this from them then my hats off to you.

You can always go more simple (read minimal function) connections to a console via tone remote control or direct E&M.

 

[mmckenna]

Yeah, the J-commands are what you want, and those are hard to come by. In all my years, I've never seen a full list of them.

If you want to interface to a console, that's pretty easy. Channel steering uses some binary inputs. Audio in/out, push to talk, carrier detect, that sort of stuff is about as simple as they can make it. Lots of off the shelf interfaces that will do that, and the pinouts/process is really well documented.

RSSI is available on the circuit board, but not easy.

 

[fontanei]

Not sure if you know but this might help you:

GitHub - W3AXL/python-radio-console: python/javscript-based radio console app for pretending like you're a real dispatcher

python/javscript-based radio console app for pretending like you're a real dispatcher - W3AXL/python-radio-console

github.com

 

[LynxVortex]

The NX-800 is easier to set up but the NX-820 can also be used with considerations. First tx and rx audio needs to be changed to filtered audio and the serial data needs to be changed from TTL to RS-232 on the rear DB15 connector. These are mods internal to the radio.

Second is a big stumbling block. You need the command structure for remote control via the serial line. Kenwood holds this information pretty close to their chest. Usually only released to authorized developers. If you can wrangle this from them then my hats off to you.

You can always go more simple (read minimal function) connections to a console via tone remote control or direct E&M.

Thanks for insight. Could you please elaborate on how to implement simple, minimal function connections to a console via tone remote control or direct E&M? Specifically, what wiring and hardware modifications are required for this approach?

Yeah, the J-commands are what you want, and those are hard to come by. In all my years, I've never seen a full list of them.

If you want to interface to a console, that's pretty easy. Channel steering uses some binary inputs. Audio in/out, push to talk, carrier detect, that sort of stuff is about as simple as they can make it. Lots of off the shelf interfaces that will do that, and the pinouts/process is really well documented.

RSSI is available on the circuit board, but not easy.

Thanks for the Tips. I’m curious about accessing RSSI on the circuit board. Could you provide more details on how to tap into RSSI using binary inputs and the relevant pinouts? I'm trying to figure out a reliable way to read RSSI values from the board, given that it's not straightforward.

Not sure if you know but this might help you:

GitHub - W3AXL/python-radio-console: python/javscript-based radio console app for pretending like you're a real dispatcher

python/javscript-based radio console app for pretending like you're a real dispatcher - W3AXL/python-radio-console

github.com

Thanks. I'll definitely check out the GitHub link for further reference

 

[mmckenna]

Thanks for the Tips. I’m curious about accessing RSSI on the circuit board. Could you provide more details on how to tap into RSSI using binary inputs and the relevant pinouts? I'm trying to figure out a reliable way to read RSSI values from the board, given that it's not straightforward.

Rather than me typing all of that information out, you'd be able to get the information off the Kenwood In Depth manuals for the particular radio.
The service manual will give you the RSSI points on the radio.

 

[ramal121]

The RSSI points in a Kenwood radio only provide an arbitrary voltage in relation to the signal strength. You would have to parse this voltage and translate it into a meaningful value. Kenwood radios do this internally from a button programmed as Maintenance and display the reading in dBm. I don't think you can get the displayed value out to an external device though.

Tone remote is a way to remotely control a radio from another point. It utilizes phone lines and therefore the separation can be very far. To do this the console needs to provide the EIA function tones along with the audio into a telephone style interface.. At the radio end an adapter is added to the radio to accept the audio from the phone lines and interface the separate transmit, receive, PTT, channel change and whatever else to the radio. The manufacturer of the adapter will provide instructions on how their device needs to be hooked up.

Tone remote - Wikipedia

en.wikipedia.org

In a direct connection the radio is connected right to the console. Audio and logic functions are all separate. Following is a hookup diagram to a console. The console here can use either unbalanced or balanced audio and two charts show how both are connected.