The 6&2 (TT 526) has provisions for Hard keying an amplifier relay. Seperate outputs for 6 and 2 meters keying relays. The manual says "Maximum voltage and current that may be present from the amplifier at this jack is 13.8 VDC and 100 mA." The same statement is true for both 6 and 2 meter jacks. Hope this helped. 73, Don, NN8B