Path: utzoo!telecom-request Date: 15 Apr 91 02:57:06 GMT From: Stephen Tell Newsgroups: comp.dcom.telecom Subject: Re: My New Toy: Call Forwarder From Radio Shack Message-ID: Organization: University of North Carolina, Chapel Hill Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 293, Message 5 of 11 Lines: 55 In article winslade@zeus.unomaha.edu (JOHN WINSLADE) writes: > In a recent article, Patrick writes: >> Over the weekend I bought a CPS-200 Call Forwarding System from Radio >> Shack. At the local store here, they had one left, marked down to >> $29.95, and I thought that price alone made it worthwhile. Based on discussion here I went and looked at one, and then bought the last one they had here in Chapel Hill. > That's a very interesting use for the unit. Am I correct to assume > that the reason it is being closed out is that it is almost useless as > a 'real' call diverter because (among other things) it simply bridges > the two lines which results in the acoustic efficiency close to that > of tin cans and string? The last page of the instruction booklet contains a schematic for the unit. This is really why I bought it. Its tiny; use a magnifying glass or enlarging xerox machine. There do appear to be some opamps and stuff between the isolation transformers (one per line). I haven't analyzed the circuit yet. The heart of the thing is a 40-pin DIP with smaller-than-usual pin spacing. Its obviously one of those single-chip computers, although I don't recognize it: The schematic calls it a TMS7DC42. The chip itself is labeled: TCT1061 MAS (delta) 727 02 Where (delta) indicates a symbol that looks a lot like the greek letter of that name. Most of the pins on the chip are clearly I/O lines; the pins are labeled on the schematic: A0-7, B0-7, C0-7, D0-7, INT1*, INT3*, VSS, VDD, MC, RESET*, XTAL1, and XTAL2. Anyone recognize this beastie? I haven't done much investigating yet. If I can't find out what chip this is, I may just desolder it and wire the I/O pins up to an 8052 based board or somthing. Of course I'll get to do software from scratch that way, but I probably couldn't read the code out of the chip that's in there. Its probably a mask-programmed thingy. It looks like a good toy for someone who's comfortable with a soldering iron and EPROM programmer. If I find out anything more I will follow up if there's interest in projects based around this thing. Steve Tell tell@cs.unc.edu H: +1 919 968 1792 #5L Estes Park apts CS Grad Student, UNC Chapel Hill. W: +1 919 962 1845 Carrboro NC 27510