>In message <3448A084.41B4@cousens.her.forthnet.gr>, Peter Cousens > writes >>sorry its ot but I'm desperate >> >>Anyone have the pinout or data sheet >>for Ferranti ZN470 circa 1983 ? >>It's still listed in a Plessey 1991 shortform >>under telecoms as a (telephone) microphone amp >> >>General Electric(www.gpssemi.com) have nothing on >>their site, nor does giicm >>and searches turn up nothing but misses ! > >It isn't in the 1988 Plessey Linear IC Handbook. > >Leon >-- From page IC25 of the 1983 Ferranti QUICK REFERENCE GUIDE Description: "The ZN470AE was developed for use with an electret transducer, to replace the carbon transmitter in telefony (sic) systems. The amplifier contains a bridge to allow dual polarity operation. The high input impedance makes it suitable for use with high or low impedance microphones, providing the microphone gives a high output voltage." Powered from telephone lines 4 gain settings by adjustable links provides 25db nominal other bulleted features I didn't copy 1 = no function shown (maybe common for gain adjustment links?) 2 = GT1 3 = GT2 6 = GT3 7 = one side of LINE 8 = other side of LINE 9 = BIAS (for electret?) 14 = +VE I/P 13 = -VE I/P Reg Neale