I am using a Kenwood TS-130S, which has only a 1-pole jack for the key (it is a 1/4" telephone jack, aka "monoaural", tip and barrel only). I know that I need to have an aftermarket keyer to operate with a two-paddle key, whether I use the two-paddle device in "iambic mode" (with squeeze function), or not.
I want to know whether keyers are able to plug directly into my TS-130S "KEY" jack, or whether I need to make internal connections and/or modifications (and if so, what are the implications of the mods).
I have looked at SKC Keyer see QRP_Guys website, or the Open CW Keyer SourceForge_home-page, or perhaps the Nano Keyer nano-keyer website, or the K3NG keyer [RadioArtisan_homepage], and advice from call sign AC0C about keyers.
To be explicit: I am not asking for a direct recommendation for any of those keyers. I am looking for an answer, preferably based on direct knowledge (not speculation), as to whether the radio connection on those keyers is 1-pole or 2-pole. In other words: Do any of the commonly available keyers ONLY work with radios that came equipped with two-paddle key inputs from the factory? OR, Do all keyers work with radios factory-equipped for straight-key (or Bug) inputs?
I do know that, "back in the Day" when the shift was made from straight-and-bug keys to two-paddle keys, the "Keyer" was invented to generate timed dits, and timed dahs, from one paddle and the other --- and so to allow use with older radios. But modern radios have this circuitry built in, and so wonder why there are still so many choices of Keyers.