I'm trying to modify my 88-ACR to work with the KCS specification. Does anyone know where the information on modifying the 88-ACR to read/wrote KCS audio is? Also, I was wondering if anyone ever looked at this card? The XR210 chip MITS used for demodulation of the FSK signal is capable of MODULATING too. (with both mark and space frequencies). Does anyone know why they would have used 5 ICs and a few opamps to do the modulation when they could have used the other half of a chip already present? Grant