<2708 (looks like 12 volts according to a spec sheet in one of my <books.) 2708 is three voltage for operation (+5, +12, -5) programming is for programming CS/ must be 12.0v and program pulse is 26v <2716 25 volts 27c16 12.5 TI2532 25v differing pinout and programming spec. <2732 25 volts <2732A 21 volts <2732B 12.5 volts <2764 21 volts <27C64 21 volts <2764A 12.5 volts Later ones are generally 12.5v. Some require different Vcc when programming as well. Also the part numbers given do not always match given vendors for a stated programming voltage Allison