Xref: utzoo comp.protocols.appletalk:5022 comp.sys.mac.comm:2128 Path: utzoo!utgpu!watserv1!watmath!att!rutgers!gatech!udel!haven!mimsy!mojo!russotto From: russotto@eng.umd.edu (Matthew T. Russotto) Newsgroups: comp.protocols.appletalk,comp.sys.mac.comm Subject: Re: do I need phone net connectors? Message-ID: <1991Jan10.032251.29066@eng.umd.edu> Date: 10 Jan 91 03:22:51 GMT References: <1991Jan8.090043.25113@sics.se> <1991Jan8.112500.14143@d.cs.okstate.edu> <1991Jan9.175029.23835@sics.se> Sender: news@eng.umd.edu (C-News) Organization: College of Engineering, Maryversity of Uniland, College Park Lines: 31 In article <1991Jan9.175029.23835@sics.se> boortz@sics.se (Kent Boortz) writes: > >by Robert Minich > >> A straight null-modem cable should do fine for two LocalTalk devices however, >> Kent is wrong about (mac<->mac) == (mac<->modem) == (LW|IW<->mac). [Did >> that come out right?] The exception is the modem. Serial devices come in >> two flavors, Data Terminal Equipment (DTE) and Data Comm. Equ. (DCE). >> When wiring DTE<->DCE, the pins labeled Tx (transmit) on both devices >> are connected together while DCE<->DCE cables have Tx<->Rx wiring, >> eliminating the need for a modem, thus the null-modem cable. > >IF the modem has an MiniDIN-8 connector, otherwise I can't use an >ImageWriter cable, I assume I was right even for mac<->modem. Apple >did the right thing leaving this messy RS-232C DTE, DCE... You have >never to worry about connecting output to output using two equipment >with the Apple MiniDIN-8 standard and cables. I don't even think >there is something you can call a NULL-cable in this standard because >there is only one cable wiring needed. The only modem I have seen with an 8-pin connector is the Dove Faxmodem--- and they have a wire with a connector that plugs right into the mac. The Imagewriter cable is definitely a null-modem of sorts-- it swaps the TxD/RxD pins. You do need other cable wirings-- extension cables need to be straight through, and the cables I've seen used to connect the ports to AppleTalk in the wall are straight through (though with a change in the boxes in the wall, this need not be the case). -- Matthew T. Russotto russotto@eng.umd.edu russotto@wam.umd.edu .sig under construction, like the rest of this campus.