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Amplifier Keying Interface

2.00 LBS
Calculated at checkout


The model 318 Amplifier Keying Interface provides an excellent means of keying a non-QSK amplifier from a full QSK transceiver.  The Amp Key Interface allows for either closure to ground or positive key voltage during transmit.  Four controls/indicators are found on the front panel.


  • Manual dropout delay control allows for 100 ms to 2 seconds of transmit delay
  • "KEY" LED provides a visual indication that a key signal is applied to the amplifier
  • Delay/Bypass switch eliminates delay and keys amp relay directly from radio transmit line.
  • PTT button provides a convenient means of keying the radio while tuning or testing the amplifier.
  • Two DIN connectors for exclusive use with the 599/599AT Eagle and Eagle accessories
  • DC power connector for +12 to +14 VDC power source (Female RCA 40 mA max)
  • Amp Key jack (RCA Phono Connector) provides a relay closure to key the amplifier


The 318 Interface was designed for direct connection to a TEN-TEC Eagle transceiver.


Here is a brief description of what the 318 can do for you:

  • Control an external preselector that is in the antenna line (provided it has relay switching, in and out).  You don't have to open the Eagle to install the dual-phono jack mod if using the 318 this way.
  • Control a noise canceller (like the ANC-4);  You will not need to open up the Eagle and install the dual-phone jack modification if using the 318 this way.
  • Control of the Accessory "EXT RX ANT Switchboxes," like the ones from DX-Engineering, and Array Solutions.  No need to open up the Eagle and install the dual-phono jack mod when using the 318 this way.
  • Connect the model 712 plus have a keying line for the computer to run digital modes both simultaneously connected.
  • Connect a straight key and use it to key CW without removing the normal squeeze paddle connector on the Eagle.  All without removing the DIN plug from the model 712 or AMP KEY line.
  • You may plug-n-play 2x RCA phono plugs between the 318 and any amp (QSK or not) and control the amp key line without soldering a connection.
  • Adjust the hang time delay for an amplifiers T/R relay to allow a more comfortable operation for people who do not like QSK keying


What's Included:

  • 8 pin to 8 pin DIN cable measures 6.5 ft.
  • Dual RCA audio cable for keying lines measures 6 ft.

 318 Instruction sheet download


Power Requirements: 12 – 16 VDC @ 40 ma max.
(keyed, delay set to minimum)

Delay Time Range: 100 – 2000 msec (approximately)

Keying Voltage (“+ Key” from radio): +4 to +30 VDC @ 3 ma maximum

Output Relay Contact Ratings: 2A @ 30 VDC
0.5A @ 125 VAC

Relay Contact Activate Time 2 / 4 ms typical / max

Relay Contact Release Time 4 / 6 ms typical / max

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Product Reviews

  1. Great for Ten-Tec Transceivers interfacted with non-QSK Amplifiers !

    Posted by Williaml Bibeau on 2nd Feb 2015

    I bought an Argonaut VI some months ago and occasionally hook it up to my non-QSK amplifier. The 318 gives me a nice adjustment of the amplifier relay release time so that I don't have to hear the constant relay clicking in the amplifier.

    I like it so much that I'm thinking of buying another one for another station setup here in the shack.

    Bill Bibeau

  2. Works great!

    Posted by Eric - W9WLW on 11th Feb 2014

    Works as advertised, and really expands the Eagle. I really like the push button on the front "Push to Test" as a quick way to key up the radio/amp. I appreciate that cables come with it too.

    73 - Eric

  3. Make Your Eagle Soar with the TT-318 Interface

    Posted by Ai4CO, Randy Moore on 2nd Jul 2012

    I really wanted to be able to have my TT-712 audio interface and my amplifier connected at the same time. I was planning to make a interface of my own that would expand the interface capabilities of the Eagle when I discovered the solution. The TenTec 318 Keying Interface. It plugs right into the DIN connector on the back of my Eagle. My amplifier, model 712 audio interface, and a remote key can all be connected at the same time. The 318 is a great interface that expands the capabilities of my 599AT Eagle and well worth the $89.00.

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