ctk@ecsvax.UUCP (03/31/84)
Our research group recently bought 4 Datec Pal 1200 baud modems (we got a good
deal on a state contract). One is for my use at the office and at home. At
my office the thing works fine with a Televideo 920c. At home I have an IBM
PC and the PAL fails *even the loopback test*. What is the deal here? Datec says that the problem is either with the
cable or IBM. Has anyone else had this problem? What is the proper Datec to ibm
interface? I am using a very old PC and an AST megaplus II card. I need help
if the DATEC PAL is to be more that a very expensive boat anchor. By the way,
the more expensive Datec 212 also worked in the office and failed at home.
C.T. Kelley
Dept. of Math.
N.C. State U.
Raleigh, N.C. 27650
decvax!mcnc!ecsvax!ctkctk@ecsvax.UUCP (03/31/84)
Well folks, the problem was the following. I made my cable from ribbon cable
and solderless connectors that I got from Radio Shack. This arrangement
managed to reduce the voltage to the point where the Datec didn't konw
I was there. When I reduced the cable length to 10" all was well with the
regular 212. The PAL passess the local loopback test but will not auto-dial
since the Rom routine in the IBM wants to see DSR which the pal does not
provide. Tying pins 6 and 8 should fix this.
Watch those cheap cables, -- ctkdoc@ecsvax.UUCP (04/02/84)
I use the Datec PAL 212A with my IBM-PC at home and at work (which are two different phone companies, neither Bell) and the Datecs work fine in both places. How many wires do you have in your cable - the Datec and the IBM Async Board both use 1,2,3,5,6,7,8,20. Some older modems and acoustic couplers were sufficiently primitive that they totally ignored some of the lines, so that may be your problem. It seems simple enough to swap cables with someone to see if it is the cable. You might also find someone with a Hayes 212A attached to their IBM-PC and swap to see if that also fails at home. The Hayes has the same line use characteristics and the Datec PAL 212 is designed to emulate most of the Hayes commands. I really like the Datec products (I have some Datec 30 acoustic couplers that have been lifesavers in General Telephone land in the past, and are still going very strong. I expect the PAL to do the same.), but I have no connection to the Datec company except as a satisfied user. Doc Muhlbaier Duke - Biometry decvax!mcnc!ecsvax!doc
mjg@ecsvax.UUCP (04/02/84)
I have had trouble with Datec 212 modems also. In my case, however the problem was the reverse i.e. it would work at home and not in the office because the office uses a PABX which expects a very short loop to the phone and consequently will not recognize off hook. I found I had to manually take the phone of hook to draw enough current to trip the pabx before dialling. A second problem is that the modem will not dial if it does not see the correct RS232 status line - I think it is DTR - data terminal ready. Check the lights on the front. When you power up, before dialling you should see the TR light\ on, if you don't then it won't originate a call. Mike Gingell decvax!mcnc!ecsvax!mjg