Being K3 owner and at the same time contesting enthusiast, I am often falling into situation where the radio has to connect to multiple pieces of equipment - no matter if it's a visited shack or complex multi-op setup. The radio itself provides a lot of options and ways to interface external devices through a single DB15HD ACC connector. While availability of all the ACC signals is something really great, there are two real life challenges to manage them - routing different signals to different devices and splitting one and the same signal to multiple devices. The first challenge can be addressed with simple Y-cable. The second one requires additional circuitry in order to ensure that peripherals don't interfere with each other (e.g. different PTT voltages) on one hand, and on the other - to ensure that ACC outputs don't get overloaded (e.g. band data). All these, combined with the need of some simple way to connect to ACC pins, led to the development of K3 ACC-tender.
ACC-tender main features are listed here and described in more details throughout this page:
- Laser-cut, powder coated, laser-engraved aluminum box that attaches to the top of K3
- Device width is the same as K3's, mounting holes are in line with K3 cover screws
- Connects to K3's +12VDC output and ACC connector
- Splits to 3 fully wired ACC DB15HD connectors, each of them with separately buffered outputs*
- 7 RCA connectors giving direct access to three ACC input pins (EXT ALC, PWR ON, FSK IN) and buffered access to four ACC output pins (DIGOUT0, DIGOUT1, TX INH, KEY OUT)
- ACC and RCA connectors are placed on rear panel
- RFI blocking implemented on all ACC-tender inputs and outputs
- Advanced TX INHIBIT circuit to connect up to 4 inhibiting devices in parallel and allow K3 to go on the air only after all TX INHIBIT inputs are closed
- TX INHIBIT enable/disable control on per input basis with DIP switches on front panel
- All TX INHIBIT inputs have voltage level converters that make them +12V tolerant in order to ensure compatibility with legacy devices
- Red LED to indicate unit power status
- Green LEDs to indicate TX INHIBIT input status
*Except "K3 ON" output
Installation and connection
ACC-tender can be either freely positioned around your K3 or fixed on top of it with provided mounting screws.
ACC-tender comes with DB15HD cable ready to connect to K3's ACC and power cable to connect ACC-tender's power input to K3's 12VDC OUT RCA. Connections to ACC-tender's ACC DB15HD outputs are established in absolutely the same way as connection to K3's ACC output. RCA connectors on ACC-tender connect tip to the respective signal and sleeve to ground.
Once powered, ACC-tender will indicate this through the red LED on front panel.
Advanced TX INHibit
K3 has one dual-personality pin on its ACC connector - pin 7. It can be configured to behave as either output providing "K3 ON" signal or input having TX INHibit function. ACC-tender was designed primarily for contest environments that rely on TX INH for transceiver interlocking and utilizes builtin circuit to remove inhibit on K3 only after TX INH signal on all the 4 inputs (3xDB15 and 1xRCA) goes off. This circuit ensures that all inhibit-aware devices connected to K3 are protected from unintentional RF while keeping switching time equal to the slowest one. In addition to that, TX INH circuit inputs are equipped with level converters that allow voltages higher than 5V to be fed on TX INH inputs without additional circuitry.
For cases where TX INHibit is not needed but K3 ON is required, ACC-tender allows bypass of the inhibit circuit. Care should be taken in such situations because K3 ON signal on ACC-tender connectors is not buffered and goes directly to K3's ACC without any buffering.
Pricing and availability
ACC-tender costs $185, shipping excluded. Please use the site contact form for inquiries! Paypal and bank transfers are accepted payment methods.