bshafer@udenva.UUCP (bshafer) (10/23/86)
We will be replacing some very ancient dial-in modems (some of them 14 years old) in the next few months and I am seeking information and others' experiences with dial-in modems. Our criteria are reliability, reasonable price, maintainability and good vendor support. We would like a rack mountable 2400 (V.22 bis, V.22 A or B), 1200 (Bell 212A) and 300 (Bell 103) compatible modem. We would like it to support originate/answer and autodial (Hayes protocol is ok but not essential). They will be placed on our MICOM data switch and pooled for both incoming and outgoing calls to/from our VMS and Un*x VAXen. We need 24 to begin with and would be interested in selling the standalone compliment(s) in our Computer Store. The issue of error correction is unclear to me. Not the need so much as the how. Almost everyone is now selling modems with various levels of MNP. My question is why choose a proprietary protocol over something like X.25? (Yes somebody does make an X.25 2400 baud dial modem - I think it is General Datacomm). It also occurs to me that these protocols are more than likely burned into PROMs. If that is the case, are any of the vendors suggesting that if something other than the protocol they sell becomes the standard that they will have a cheap upgrade path? I would appreciate any advice and I give my thanks in advance. If I get enough responses I will post a summary to the network. -- ---------------------------------------------------------------------- Bob Shafer | ... {hplabs, seismo}!hao--\ CaIR | ... ucbvax!nbires----------> !udenva!bshafer University of Denver | ... {boulder, cisden}-----/ Denver, Colorado 80208 | Phone: (303)871-2091 ----------------------------------------------------------------------
zemon@felix.UUCP (Art Zemon) (10/30/86)
I have had excellent results using various Racal Vadic modems over the last five years. Right now I have eight rack mounted VA4224 modems (2400/1200/300 baud with MNP) in the computer room. In users' homes are a variety of US Robotics, Prometheus, and Racal Vadic modems. By far the most reliable units are the RVs. My favorite, and the only type I now buy for home use, is the Racal Vadic 2400PA. It is essentially a standalone version of the 4224 with some additional "user friendly" features like a dialing directory and EEPROM configuration instead of DIP switches. I did a bunch of side-by-side when I decided to move to 2400 baud modems and found that the Racal Vadic really did get fewer line errors than the USR Courier (RV running without MNP for this test) and the Hayes 2400 and all the others that I tested. I did not try a NEC so I cannot give you a direct comparison. In closing here is my general advice for buying modems and stereos: Spend a lot of money. Dollars seems to be directly proportional to the quality of the analog circuitry. (Of course you also need to find reputable dealers with roughly equivalent prices for this to work.) Feel free to call me if you want to talk about this stuff. (714)966-2344. -- -- Art Zemon FileNet Corporation Costa Mesa, California ...! {decvax, ihnp4, ucbvax} !trwrb!felix!zemon