Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ima.UUCP Path: utzoo!decvax!ima!johnl From: johnl@ima.UUCP (John R. Levine) Newsgroups: net.dcom,net.lan Subject: Ethernet - RS-232 or modem multiplexers? Message-ID: <189@ima.UUCP> Date: Sun, 17-Aug-86 18:02:28 EDT Article-I.D.: ima.189 Posted: Sun Aug 17 18:02:28 1986 Date-Received: Sun, 17-Aug-86 22:40:48 EDT Reply-To: johnl@ima.UUCP (John R. Levine) Distribution: na Organization: Javelin Software Corporation Lines: 68 Keywords: Ethernet modem multiplexer Xref: ima net.dcom:406 net.lan:333 Summary: Anybody know of any good ones? We have an Ethernet with about 40 IBM PCs and the like on it, along with a 3Com 3server and a PC AT with a big disk, which act as disk servers. We're currently running 3Com's EtherShare disk server software, and plan shortly to switch to 3plus which is based on Microsoft Networks, and is so quite similar to the software for the IBM token ring. Some of us need to dial out now and then to various outside machines. At this point, we have regular modems on four of the machines, but the demand is increasing and I need to do something about it. An obvious possibility would be to buy cheapo modems for the machines that need them, but this is a poor solution since it only forestalls the day when everybody needs a modem, and is quite expensive not just because of the modems, but because we'd need to buy several expander boards for our PBX to provide phone lines for the modems. We can't just share phone lines with people's existing phones because the phones in the offices are all-digital ROLM phones, and although ROLM does have an option to put RS-232 plugs on the ROLM phones, it costs a fortune. I suppose another possibility would be to run RS-232 wire and get a small data PBX, but that'd be expensive and a lot of work -- pulling wire is a major pain because our offices have real walls and when we prewired the offices for Ethernet before the walls went up, we thought we were done. Besides, we already have every single machine in the office plugged into the Ethernet. What I'd like to find is a box that plugs into the Ethernet and has some RS-232 ports on it, and software so that users on the PCs can seize a port, dial out through terminal emulators, and give the port back when they're through. It's sort of like a data PBX, but with an Ethernet in the middle and PCs rather than terminals on the front. Here are the possibilities that I have found, but I'd like information on experience that people have had with these or other similar equipment. I am not afraid of doing a moderate amount of software development if it's worth the effort. -- Bridge Communications has a package for their CS/100 box which seems to do just what we want. Unfortunately, it's overkill -- the Bridge box has 16 or 32 ports and speaks every protocol known to Western humanity. Consequently, it's kind of expensive. -- 3com lets you plug modems into the back of your 3server, but only to internetwork among 3plus networks, or to dial into the 3server from a remote PC, at which point the remote PC acts like it's connected to the 3server by a 1200 baud Ethernet. Useful, but not what I want. Did 3com ever think of a network based terminal multiplexor? Well yes, actually, they did, and if I wanted 3270 terminal emulation they'll sell me that, and they even wrote the PC software for the Bridge system above. So can I dial out through the 3server? Well, no, the way they wrote the 3server software makes it very hard so don't hold your breath. Feh. -- DEC has recently announced the terminal servier 200 which, unlike the 100, is reputed to be of use with other than DEC hosts. It's still a little pricey, but I'd like to hear how it works and how you talk to it. -- Codex has a new line of Ethernet equipment which includes the 4020 box consisting of 4 RS-232 ports, Ethernet interface, and unspecified other guts for $1000. Looks promising, but I've had trouble getting any useful information from Codex. It appears that they want you to buy this box in a combination with other stuff so you get the effect of an RS-232 data PBX that happens to have an Ethernet in the middle. I don't know if they document their protocols. I don't even know if they really make it or whether it's made by some other Motorola subsidiary and relabeled (like the UDS modems that they also sell.) Advice and suggestions are appreciated. TIA. -- John R. Levine, Javelin Software Corp., Cambridge MA +1 617 494 1400 { ihnp4 | decvax | cbosgd | harvard | yale }!ima!johnl, Levine@YALE.EDU The opinions expressed herein are solely those of a 12-year-old hacker who has broken into my account and not those of any person or organization.