aaron@bbm.UUCP (Aaron Burns) (01/13/90)
About 3 months ago I came up with a cheap way to give interested parties on other floors in our building a fast connection to our Xenix systems - Bell 'in-house data channels' (direct phone lines) coupled with short haul modem eliminators (SHM's, also line drivers). Total connection cost $370 (Canadian) plus $6.90/month for the line. As these modems are self-powered in their most compact form, I called Computone to confirm that their cards could power at least ten SHM's. Computone's technical people said ok, "you shouldn't have any problem". The first link went in between a Computone Intelliport AT-16 and a PC-AT with Kermit emulating a VT-100 on a 'standard' serial port, and is functioning properly at 19,200 between two floors. The second link was set up later between a Computone Intelliport AT-8 (on a different system with two such cards) and, again, a PC emulating a VT-100. It didn't work. After much trial and tribulation (no-one ever suggested a power problem, and every component tested good in isolation), we discovered that none of the SHM's could do a loop-back while on the AT-8...but worked just fine off a standard port and an AST 4-port dumb card. The conclusion is insufficient juice to power the SHM's. We backed this up by putting a longish (155 foot) cable between the two systems (ie between an AT-16 and an AT-8). While "Managing UUCP and Usenet" (O'Reilly and Associates) states that a 9600 baud connection is feasible out to 250 feet, this cable (shielded, low-capacitance) kept losing dtr, and (with -clocal in the gettydefs entry) garbled transmissions at 9600. When the AT-16 end was hooked to an AST port, dtr became stable and data transmission was flawless. It appears that the Computones just don't put out much of a signal. I don't have test equipment to directly confirm this. I will call Computone today, but - how could they help? After all, the cards work OK with just terminals, and that is what they're advertised for. If they do say anything usefull, I'll let you know. Anyone with similar experiences - please tell us! -- Aaron 'crash and' Burns "Nothing I say on the net is binding Metro Works to our corporation" Toronto, Ontario "Life is a forge, and the purest metal (416)392-4310 comes from the hottest fire" aaron@bbm.UUCP ...utzoo!yunexus!stpl!bbm!aaron
bob@consult.UUCP (Bob Willey) (01/15/90)
I can give you our experiences. We have used the Computone Intelliport AT8 and AT16's for up to 500 ft.!!! That's 500 ft!!, using GOOD QUALITY cable. This is running Wyse 60 terminals at 9600 baud. We had a lot of reservation about doing this, as it is DEFNITELY not recommended NOR did anyone say that this would definitely work, but it did. We have about 8 terms at 500ft, and another 4 at 440 ft. Have been running over 6 months now, without a hitch (Yet..). We have done this several times with other cards, with failures occuring at about 200-250ft. The Wyse 995 board breaks down at about 200 ft or so. But then again, most of these boards were not designed for this type of stringent usage. Hope this helps. -- .. Computer Consulting Service .. Bob Willey, CDP .. .. P.O. Drawer 1690 .. uunet!consult!bob .. .. Easton, Maryland 21601 .. (301) 820-4670 .. ...............................................................