T1-FT817 Elecraft Remote Control Adaptor T1 to FT-817.
The Elecraft T1-FT817 is a great accessory for all low-power radio enthusiasts as it is small and light enough to take anywhere!
It is an 18in long screened cable fitted with a mini-DIN plug for the 817's ACC socket, and a jack plug that plugs into the side of the T1. Inside the mini-DIN plug, is a circuit board made with SMD components, including a tiny microprocessor control unit! It's powered by the FT-817 itself, drawing a small current. The MCU monitors the band data signal from the FT-817. When the band changes, it turns on the T1 and sends it band information, allowing the antenna to be automatically tuned to the new band!
The Adapter is an amazing peice of equipment, it allows you to switch from band to band and it won't tempt you to send a burst of spectrum-polluting RF to re-tune the antenna.