joel@gould9.UUCP (Joel West) (05/08/86)
We're moving into new space and I'm tempted to wire up some of the
offices (about 5) for RS232. We currently have a lot of terminals,
modems, phone lines and 1 micro, but a workstation or MicroVAX seems
likely in the next year.
First, how many wires would I need? I was guessing 6 but a lot of
the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD,
DTR) or 9 (add FG). I guess that requires 10-conductor plenum.
(INMAC, $.95/foot after 100 feet)
Next, I need a source for a patch panel to hook up such a connection. I've
found two sources for DB-25 panels (60-100 depending on the mounting),
then you have to populate it with DB-25 connectors. Add to that 9-wire
patch cables (Inmac shielded, $19 ea quantity 5) and you have a few
hundred bucks.
Even better was a patch panel based on 6- or 8-wire mini-modulars
and coiled patch cables. But I can't find it in any of my catalogs
(Inmac, Dartek, Misco).
Any advice or tips would be most appreciatedkkk
--
Joel West (619) 457-9681
CACI, Inc. Federal, 3344 N. Torrey Pines Ct., La Jolla, CA 92037
{cbosgd, ihnp4, sdcsvax, ucla-cs} !gould9!joel
joel%gould9.uucp@NOSC.ARPAphil@amdcad.UUCP (Phil Ngai) (05/09/86)
In article <532@gould9.UUCP> joel@gould9.UUCP (Joel West) writes: >We're moving into new space and I'm tempted to wire up some of the >offices (about 5) for RS232. We currently have a lot of terminals, >modems, phone lines and 1 micro, but a workstation or MicroVAX seems >likely in the next year. > >First, how many wires would I need? I was guessing 6 but a lot of >the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD, >DTR) or 9 (add FG). I guess that requires 10-conductor plenum. >(INMAC, $.95/foot after 100 feet) You can get by with 6 for terminals and modems (TD,RD,DTR,DCD,SG) with the right adapters. I say 6 because we have used 6-wire telephone cable, even though I only listed five signals. We currently use 8-wire cable. This would allow us to run RTS/CTS for "hardware" flow control someday. And there is a cheap adapter (WECO 258A) which breaks out a 25-pair cable to 6 8-wire outlets. We like the phone wire technology because it is dirt cheap due to massive economies of scale yet engineered to last forever (well, 40 years). To go from the phone wire to DB25 we use MOD-TAP adapters. They work very well. Sometimes they work better than a 25-wire RS-232 cable. (I have a nasty flame for one of our vendors which I won't post here but would be happy to relate by mail.) >Next, I need a source for a patch panel to hook up such a connection. I've >found two sources for DB-25 panels (60-100 depending on the mounting), >then you have to populate it with DB-25 connectors. Add to that 9-wire >patch cables (Inmac shielded, $19 ea quantity 5) and you have a few >hundred bucks. > >Even better was a patch panel based on 6- or 8-wire mini-modulars >and coiled patch cables. But I can't find it in any of my catalogs >(Inmac, Dartek, Misco). Indeed, MOD-TAP also makes patch panels based on 6 or 8-wire modulars. We have tried them and they work quite well. You might want to consider the use of phone company "punch blocks" (66M). We use them for most of our terminals. Again, they are cheap ($5 terminates 100 wires) yet engineered to last forever. Also, they look complicated and our users are too scared of them to change them behind our backs, which we find desirable. In reality they are very very simple. Note that ATT and DEC are starting to play with running RS232 over phone cable. Their stuff probably works, but we've been using MOD-TAP for a long time and see no reason to change. Another option is to run Ethernet transceiver cable. You get 8 very well shielded conductors and you can convert to Ethernet without pulling new cable. It's a little more bulky and expensive but pulling cable is usually the most expensive part anyway. -- If a reactor melts down in Russia will they call it the America syndrome? Phil Ngai +1 408 749 5720 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil ARPA: amdcad!phil@decwrl.dec.com
henry@utzoo.UUCP (Henry Spencer) (05/11/86)
> >First, how many wires would I need? I was guessing 6 but a lot of > >the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD, > >DTR) or 9 (add FG)... > > You can get by with 6 for terminals and modems (TD,RD,DTR,DCD,SG)... Actually, for terminals (and only for terminals) you can get by with 3 wires (TD, RD, SG). We do this routinely. This does mean that (a) you have no hardware indication of the user switching off his terminal (add DTR if you need this) and (b) if the terminal needs flow control, it and your software better be capable of using XON/XOFF (add CTS and RTS if you need hardware flow control). You will need DCD and RI, and perhaps DSR, for modems. We actually tend to use full 25-wire cable for modems, although that is considerable overkill. Note that you will quite possibly have to do some jumpering on one or both ends with the minimal schemes; your machine probably wants to see DCD on terminal lines (jumper it to DTR) and some terminals want to see various signals before they will talk (we jumper CTS, RTS, DSR, and DCD together as a generic solution). -- Join STRAW: the Society To Henry Spencer @ U of Toronto Zoology Revile Ada Wholeheartedly {allegra,ihnp4,decvax,pyramid}!utzoo!henry
swb@batcomputer.TN.CORNELL.EDU (Scott Brim) (05/12/86)
In article <11620@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: >In article <532@gould9.UUCP> joel@gould9.UUCP (Joel West) writes: >>First, how many wires would I need? I was guessing 6 but a lot of >>the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD, >>DTR) or 9 (add FG). I guess that requires 10-conductor plenum. >>(INMAC, $.95/foot after 100 feet) > >You can get by with 6 for terminals and modems (TD,RD,DTR,DCD,SG) with >the right adapters. I say 6 because we have used 6-wire telephone >cable, even though I only listed five signals. Even though in *most* cases you can get by with 6, we now *always* pull 8, having been burned in the past. Scott +++++ Scott W. Brim swb@cu-arpa.cs.cornell.edu Cornell University Theory Center {decvax,ihnp4,cmcl2,vax135}!cornell!swb 265 Olin Hall 607-255-9392 Ithaca, NY 14853
scarter@caip.RUTGERS.EDU (Stephen M. Carter) (05/12/86)
In article <6674@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes: >> >First, how many wires would I need? >> You can get by with 6 for terminals and modems (TD,RD,DTR,DCD,SG)... > >Actually, for terminals (and only for terminals) you can get by with 3 >wires (TD, RD, SG). More so, you can get away with only two wires and make the building the signal ground! We do it here at Rutgers and most of our terminals use 25 pair trunk cables with a pair for each terminal. Lengths are a long as 350 feet at 9600 bps without problems. The old school of thought suggested that removing individual ground lines would prevent ground loops. Also, it sure tells you very fast when there is a problem with the safety ground of the individual outlets... I do not suggest this method unless you know that the building has a solid ground in all areas. It sure puts a strange look on the user's faces when you come up to fix a dead terminal by a wiggle of the power plug :-)
scarter@caip.UUCP (05/12/86)
In article <11620@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: >Another option is to run Ethernet transceiver cable. You get 8 very >well shielded conductors and you can convert to Ethernet without >pulling new cable. It's a little more bulky and expensive but pulling >cable is usually the most expensive part anyway. >-- I like this idea. Provided that all runs are less than 50 meters, wire everything for db15/e-net. Use db15 <--> db25 adapter cables (I am sure you will have to make these up yourself), and as users move to workstations, use a fan-out box to connect them to the coax. I would also think that this cable would be good enough for any twisted pair networking schemes that come along...
mason@ryesone.UUCP (Dave Mason) (05/12/86)
> > >First, how many wires would I need? I was guessing 6 but a lot of > > >the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD, > > >DTR) or 9 (add FG)... > > > > You can get by with 6 for terminals and modems (TD,RD,DTR,DCD,SG)... > > Actually, only for terminals, you can get by with 3 wires (TD, RD, SG). I had a client once who only used 2 lines for terminals (TD,RD), and depended on the building grounds to be close enough (it worked). We use 4 wires (TD,RD,SG,DTR) for our terminals, and do basically what henry@utzoo suggested for straps except that our machine needed some strange jumpers (computer end). -- usenet: ..!utzoo!ryesone!mason Dave Mason, Ryerson Polytechnical Institute ..!utzoo!utcsri!mason Dave Mason, U. Toronto CSRI CSNET: mason@Toronto ARPA: mason%Toronto@CSNet-Relay BITNET: FCTY7053@RYERSON.BITNET
joel@gould9.UUCP (05/13/86)
I'd like to summarize what I've learned from all those great replies. > We're moving into new space and I'm tempted to wire up some of the > First, how many wires would I need? I was guessing 6 but a lot of > the stuff I've seen suggests 8 (TD,RD RTS, CTS, DSR, SG, DCD, > DTR) or 9 (add FG). I will probably be using 8 (FG is unneeded, some pointed out). I want to use cables for both DTE's and DCE's, so the modem control is important. > Even better was a patch panel based on 6- or 8-wire mini-modulars > and coiled patch cables. I got 14 replies, nearly all of which suggested Mod-Tap (manufactured by Darlabs, Inc. 800 252-1100). In California, a firm called Nevada Western seems also to be popular. Apparently these companies are not consistent in their assignments of the 6 (8) wires. One of the messages gave me an idea. We have 25-pair telco cable in each office left over from a previous phone system. We should be using only 3 or 4 pair for our new phone system, so I will probably use the remaining 40 wires to supply up to 5 8-line RS-232 lines. The only hitch on this is physical access to the phone cabinet, but the advantages are so significant that I'll find a way around this. Thanks for all the help... -- Joel West (619) 457-9681 CACI, Inc. Federal, 3344 N. Torrey Pines Ct., La Jolla, CA 92037 {cbosgd, ihnp4, sdcsvax, ucla-cs} !gould9!joel joel%gould9.uucp@NOSC.ARPA
phil@amdcad.UUCP (05/14/86)
In article <545@gould9.UUCP> joel@gould9.UUCP (Joel West) writes: >I got 14 replies, nearly all of which suggested Mod-Tap (manufactured >by Darlabs, Inc. 800 252-1100). In California, a firm called Nevada >Western seems also to be popular. Apparently these companies are not >consistent in their assignments of the 6 (8) wires. I was never able to get a schematic of their patch panels from Nevada Western. MOD-TAP is very knowledgeable and cooperative. They understood the information I wanted and provided it. With only 8 wires I could ohm it out myself but without documentation from NW in principle they could change it any time. Furthermore, MOD-TAP has one model which conforms to what has as much chance as anything else to be a standard, the Western Electric 258A. The 258A uses the same pinout as you get if you have ATT install their Premise Distribution System in your plant. It is also compatible with the new devices which use 8-wire connections such as ATT's DDS DSU/CSU (2556, etc) and switched DDS. I recommend the 8-wire technology, done according to 258A. >One of the messages gave me an idea. We have 25-pair telco cable in >each office left over from a previous phone system. We should be using >only 3 or 4 pair for our new phone system, so I will probably use the >remaining 40 wires to supply up to 5 8-line RS-232 lines. The only hitch >on this is physical access to the phone cabinet, but the advantages are >so significant that I'll find a way around this. Here's another reason to use the 258A pinout. Your offices will probably already have a 258A in them. It's a connector with 6 8-wire outlets. Let me know if you've got them. Or if you have more questions. -- Phil Ngai +1 408 749 5720 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil ARPA: amdcad!phil@decwrl.dec.com
holtzman@mit-amt.MIT.EDU (Henry N. Holtzman) (05/16/86)
In article <145@ryesone.UUCP>, mason@ryesone.UUCP (Dave Mason) writes: > I had a client once who only used 2 lines for terminals (TD,RD), and depended > on the building grounds to be close enough (it worked). We use 4 wires > (TD,RD,SG,DTR) for our terminals, and do basically what henry@utzoo suggested > for straps except that our machine needed some strange jumpers (computer end). I also once knew someone who counted on building ground. Then he went to put in a different terminal, and his rd,td became a loop at both ends. (Both the terminal and computer would get an echo of what it typed, but it wouldn't make it through to the other.) It was funny to watch, but not funny to re-wire. The moral is: Unless you are going to lock yourself into one set of hardware for the rest of your life, stay at least close to the specs. Don't just experiment with your equipment and then try to get away with what seems to work, but shouldn't. -Henry
sewilco@mecc.UUCP (Scot E. Wilcoxon) (05/19/86)
In article <2236@caip.RUTGERS.EDU> scarter@caip.UUCP (Stephen M. Carter) writes: >In article <11620@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes: >>Another option is to run Ethernet transceiver cable. You get 8 very >>well shielded conductors and you can convert to Ethernet without >I like this idea. Provided that all runs are less than 50 meters, wire >everything for db15/e-net. Use db15 <--> db25 adapter cables (I am sure >you will have to make these up yourself), and as users move to workstations, >use a fan-out box to connect them to the coax. I would also think that You should consider RJ-45 or RJ-11 (phone-style modular plugs; 8 or 4-6 wire) wiring. Last time we wired up I got RJ-45 to DB-25 connectors on the back of each terminal, with 8-conductor cables (male RJ-45 each end) to RJ-45 wall sockets. Cables have four twisted pairs and a grounded shield, connected to the wall sockets by screws (no more soldering or crimping). Longest cable at the moment is 60 feet. I found $7 RJ-45 to DB-25 connectors..about half the usual price, and it paid back real fast by reducing my time playing with cables. If you have clusters of terminals, there are converters from RJ-45 to large connectors which let you use 50-conductor wire... -- Scot E. Wilcoxon Minn. Ed. Comp. Corp. quest!mecc!sewilco 45 03 N / 93 08 W (612)481-3507 {ihnp4,philabs}!mecc!sewilco "The appeal of nuclear energy has decayed rapidly in the UUSR"