Unless the FL-101 does things differently, I would suspect it is a standard FSK input. Using it, you are not using an audio tone input. The rig is transmitting a key-down carrier, and shorting that FSK connector shifts the frequency of the carrier. Back before PC's and their audio output connections to radios, terminal units and rtty keyboards just used an open or closed connection to key the FSK inputs to various radios. Not much AFSK was used. ....Dave ----- Original Message ----- From: "riceguy" <riceguy at copper.net> To: <yaesu at mailman.qth.net> Sent: Wednesday, February 04, 2009 6:48 PM Subject: [Yaesu] FL-101 FSK Keying Query > The phono jack on the back of a FL-101 marked FSK >> Is it dry contact or a voltage input or audio ? >> I never found anything to help explain what input it needs >> Rice > ______________________________________________________________ > Yaesu mailing list > Home: http://mailman.qth.net/mailman/listinfo/yaesu > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Yaesu at mailman.qth.net >> This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html