Kenwood TK-880 Horn Honk
by Jay Banks


Note: The programming software used for this project is KPG-49D for Windows


Table of Contents

A) Pre-install (The Hardware Side)
B) Programming Issues (The software side)
C) Testing out the horn honk on an IFR
D) Vehicle Install (Hardware Side)


A) Pre-install. Parts required: KC-19 and KAP-1 (PA/HA Unite)

Install the KC-19 and KAP-1 board as per TK-880/H Service Manual (see page 20)

Notes: The KCT-19 and KAP-1 will connect as follows:

KAP-1 W2 3-pin connector (green, green, green) connects to CN5 on the 880 board
KAP-1 W1 3-pin connector (white, black, red) connects to CN3 on the 880 board
KC-19 3-pin connector (brown, red, orange) connects to CN2 on the KAP-1 board
KC-19 8-pin connector (only 8-pin connector) connects to CN1 on the 880 board

Not used in this setup:  KC-19 3-pin connector (brown/white, black, white)
                                   KC-19 2-pin connector with 1 tan (yellow?) colored wire going to it.

Turn the radio upside down, with the front toward you and the heat sink away from you.
Remove the panel and VERY CAREFULLY remove resistor R152. R152 is clearly 
labeled on the board. R151 and R152 have arrows pointing to them. Remove R152
(the 2nd from the left when oriented correctly).

Notes: Removing R152 will enable the horn honk. The TK-880 Service manual is not very clear in this area. You may experiment with the resistor settings, but in our experiments, the horn honk would not function without R152 being removed.

A fellow tech pointed out that the resistor may actually be located on slightly different locations on different 880 boards. They should still be labeled, however.

B) Programming Issues (The software side)

1. Setup the radio programming in the normal manner.

2. On the KPG-49D menu, go to Edit\DTMF

Here you will  find three tabs. Set them up like this:

Screen 1 (Decode)

Notes: The Primary Code will be the unique vehicle code for the vehicle that this radio will go into. The Primary Decode Response of Alert+Transpond will honk the horn and send a beep back to acknowledge that the horn was honked. Setting this to just Alert will only honk the horn. And interesting side note is that using the Alert+Transpond mode will make the horn honk function as an extremely rudimentary vehicle location device, because if you have multiple systems in a radio and you use the horn honk, if you get the acknowledge beep back on an isolated repeater system, you at least know the vehicle is in that area. Again, the key words in the last sentence were "extremely rudimentary."

Screen 2 (Encode)

Notes: Setting the first digit to 1000 will make the first DTMF tone longer. This is optional BUT the reason you might want to do this is because if the radio is in scan, it may not pull out in time to receive the entire DTMF tone. Or in other words, you might actually audibly hear a portion of the DTMF tone, but it will fail to make the horn actually honk.

Screen 3 (DTMF Memory)

Notes: If you want to have the ability it honk horns vehicle to vehicle, enter all the codes you want to be able to honk on this screen. And note that it is possible to put an alert on a base radio!

To honk vehicle to vehicle, you have to assign a key to have a memory function:

On the KPG-49D menu, go to Edit\Key Assignment:

Note: Keys actually used are optional. Assign desired button the Memory(RCL) function, as seen above on the "B Switch"

What this does is: When the user hits this key, it will allow them to tab, using the group up and group down keys on the front of the radio, through the list of DTMF tones programmed into the radio (see: Screen 3 (DTMF Memory), pictured above). When the user gets to the Assigned Name (A/N) in the list he wishes to horn honk, he will stop scrolling and key up using the microphone. This action will transmit the DTMF tone over the trunking system and cause the vehicle assigned that DTMF tone to honk...if all horn honk requirements are met for that vehicle at that time (e.g. vehicle not running, mic on hook, etc.).

Options: If you want the horn honk to function while the mic is off hook, go to Edit\Optional Features and put a check (click in) the empty white box next to the text that reads, "Off Hook Horn Alert."

If you want a button to enable/disable the horn honk, set a button (Edit\Key Assignment) with the "horn honk" function. If the customer does not want the ability to turn the horn honk off, do not set a button up to do so.

Note: With a horn honk button, the 880 display must show "HA" for the horn to honk. The "HA" means the alert is active. 

3) Edit the System Information

On the KPG-49D for Windows menu, go to Edit\System.

Go to each system you want the horn honk to work on and hit the "System Edit" button.

Change each "Opt Signal" setting from the default of "None," to "DTMF":

Next, while still on this screen, hit the "Group Data" button at the bottom of the active window. Make sure the box next to the text "Horn Alert," has a check in it, as pictured below:

Note: Sometimes this box seems to be checked by default when you set the Opt Signal to DTMF, however, there are cases where it does not automatically check this box, so be sure and double check.

Do the above for each system in the 880 that you want to have the horn honk working on. Note you can have the correct info in the DTMF settings, but if you do not do the above two items, the horn honk is NOT going to work.

NOTE: When programming the radio, after setting the DTMF information up the way you want it, make sure and check the little white box that says "Include DTMF Memory,":

Or optionally, if the programming is already configured for a horn honk, you can just write the DTMF information to the radio (menu: Program\Write DTMF to Radio."

Remember that in most circumstances you are going to want a unique DTMF id for each vehicle, so in most cases, you are going to have the same programming layout for each vehicle, but edit the DTMF id for each radio as you program them.

C) To test the horn honk

On the radio, go to a Talk Around or conventional channel with no PL tone. (You may have to program in a test channel, or optionally, set your IFR up to handle a PL tone). On the IFR, hit the RF button and program in the frequency of this Talk Around or conventional channel receive.

Program in the DTMF ID of the radio you are testing by hitting the program button, the DTMF button, and the 1 on the IFR keypad, followed by the DTMF code programmed into the radio.

Put the IFR in Generate mode, and hit the Execute Key, followed by the DTMF button. This will generate the DTMF tone, and if everything is set up correctly, cause the radio to beep (which will also be honking the horn when installed in a vehicle.

At this point, you can connect an ohm meter to pin 10 of the KCT-19 and ground to the body of the 880. When you set the horn honk off using the IFR, it should Ohm to ground.


D) Vehicle Install

Hook the connector up to the KC-19 (I believe this part is actually a KC-18, but I could be wrong), with a wire going into pin 10. Run this wire from the radio, installed in the vehicle, to the horn honk relay on the vehicle. This is usually located in the fuse box under the hood.

Note: You can find this by pulling relays out and honking the vehicle horn. When you pull a relay out and the horn no longer works, this is the right relay. If you are doing fleet vehicles, which are often all from the same manufacture and same year, make note of the location of this relay, for easy horn honk installs on future vehicles.

Note:  At this time we were unable to locate the relay on a new 2005 (2006?) model Ford truck. If this is the case, get a 5 pin relay, such as a BOSCH 12V relay (12V 20/30A   0 332 209 150) and purchase a small horn. Hook up Pin 10 from the 880 to pin 85 on the Bosch Relay, and hook pin 30 of the Bosch Relay, to the horn. Pins 87 and 86 of the Bosch Relay will be constant 12 volts (run 12 volts to one of them and jumper between pins 87 and 86). See the following diagram:


Note: Make sure you point the horn slightly down, so that it doesn't catch water, which could damage it.


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