barry@adelie.UUCP (Barry A. Burke) (02/16/86)
My company is relocating in a couple of months into a brand-spankin' new office space, which is this minute being constructed to our specs. I am responsible for specifiying all the data pre-wiring, and I'm not sure about what transceiver cables to spec (I'm gonna go ahead and have the xcvr cables installed in all the areas that may one day have Ethernet devices). Background: My current network consists of two Ultrix VAXen: aVAX 11/750 and a uVAX-II, and two Bridge CS/100-TCP terminal servers. All four devices are currently interconnected via a DEC DELNI (they're all in the computer room)- everything's TCP/IP. I will soon add 2 or 3 more CS/100's, 2 CS/1-SNA's, a SUN 2/160M workstation, and an Imagen 8/300 Laser printer w/ethernet interface, all TCP/IP In the new facilities, I plan on putting all the Bridge equipment on the DELNI, and connecting the DELNI to the (new) coax backbone. The VAXen, the SUN, and the Imagen will all be cabled directly to the coax. Current administration plans are to also introduce several XEROX 6085's and a XEROX laser printer to the shop- I'd like to hang them off of the same Ethernet coax (yes I realize they won't talk TCP/IP). The Questions If I look at the DEC Comms guide, I see three different transcievers and two different cables available: H4000 - the `original' DEC no-frills xcvr H4005 - the `new' DEC xcvr with post-amble/trailer checking (?) H4005 - " " " " without " " " " ...... - `original' DEC xcvr cable ,,,,,, - "802.3" xcvr cables And of course, if I look into the details, the DEC guide gives no recommendations for which to use with Ultrix+DEUNA/DEQNA. And there is some obscure warning about not using the H4005 with the DELNI under certain circumstances. Q0. What's the difference between the xcvrs and cables mentioned? Q1. Which xcvr+cables should I use for: the VAXen? the SUN? the Imagen? the DELNI? (NOTE: I'm using the `original' DEC xcvr cables now- both for the VAXen and the Bridges). On to XEROX. The XEROX xcvr cables are somewhat different (at least in spec) than the DEC cables in that while there seems to be the same number of wires, they are paired and shielded differently. Q2. Despite the differences, can I use DEC xcvr cables to connect XEROX equipment to my coax? Q3. Can I use DEC xcvrs? Which one? Q4. Is there really a "standard"? I'd like to pre-run the xcvr cables without regard to which vendors equipment is gonna get used where- I also thought that was the intent of Ethernet (semi- ;-). Q5. Any other things I should watch out for? Administrivia: For the record, I probably won't actually buy cable from DEC, but the place I do buy from will build "identical" cables to any of the above (DEC or XEROX)- usually for about 1/2 DEC's price and with 1 week delivery. I've no qualms in using any other xcvr that might be recommended, as I'm resigned to the fact that DEC probably won't give me HOOT for support of this LAN anyway. Q6. Anybody know where to get "DEC EtherJack" equivalents for less & quicker? They're sure a nice way to hide the place where the TEFLON cables meet the (flexible) office cables) I've set this article to be followed up in "net.lan", in case you want to follow any discussions it may create. I would prefer direct mail responses, however; I will summarize for the net as needed. Hopefully, I can get some quick answers, as I only have 1 1/2 weeks to get the specs to the laborers... THANKS! -- LIVE: Barry A. Burke, (617) 965-8480 x26 USPS: Adelie Corporation, 288 Walnut St., Newtonville, MA 02160 UUCP: ..!{harvard | decvax!linus!axiom}!adelie!barry ARPA: adelie!barry@harvard.HARVARD.EDU, barry%adelie.UUCP@harvard.HARVARD.EDU