I'm trying to use some Motorola Permacode filters (those used in Minitor II pagers) to make my own home-brew two-tone decoder. Does anyone happen to have the pinout for the Permacode filters? These are 4 pin devices and I suspect the pins are Ground, Power In, Audio In and Audio Out. I'm sort of groping in the dark a bit here. I'm also looking for the specific voltage used to power the filter. And finally, what's the expected output from the Permacode filter with the proper frequency input tone: a sine wave at the desired frequency (like a very high Q band pass filter)? or is there a level detector in the Permacode filter so the output is a DC value (i.e, something like low output on correct tone detect and high output otherwise)? I appreciate any advice people can provide about these filters. Thank you.