Dalavar - that might be since this is an OLD desk style brass belled Western Electric touch tone - might be reversed tip and ring which I will try later BUT a brand new Zoom modem in a PC did the same, which also might be reversed polarity. I need to check the jack with my butt set and see or even reverse them at the jack temp and see - later as I have PC service calls all day. I also need to try a newer analog KX-T (3000 series I think) single line phone I have stashed and see if it also makes tones but isnt recognized by the KSU.

EV607797 - not sure, I have to skim the manual that I have printed and see what it says if the TA624 has some parallel enable. Might be quicker to search the PDF then go to the printed manual.

All good responses and all greatly appreciated. Now to head out and see about fixing some sick computers and printers before I can look at these options.