perl@rdin.UUCP (Robert Perlberg) (05/04/86)
Is there any truth to the rumor I heard that plain RS-232 type cable
can be used to connect Ethernet transceivers?
Robert Perlberg
Resource Dynamics Inc.
New York
{philabs|delftcc}!rdin!perlphil@amdcad.UUCP (Phil Ngai) (05/07/86)
In article <546@rdin.UUCP> perl@rdin.UUCP (Robert Perlberg) writes: >Is there any truth to the rumor I heard that plain RS-232 type cable >can be used to connect Ethernet transceivers? You could probably use telephone cable if it was short enough. (six inches?) "plain RS-232 type cable" is pretty ambigious. I have been tempted to use Belden 9891 Ethernet transceiver cable for RS-232. Clearly I could convert that "RS-232" cable for transceiver cable use. I have seen people use short lengths of flat ribbon cable for transceiver cables (Interlan). If you are going 50 meters then things get a little tougher. The main considerations are that you need to supply 500 mA over 50 meters with only 2 volts of loss for the power and that the signals are differential so you ought to use twisted pair for the transmit/receive/collision signals. There are also crosstalk requirements which are usually met by shielding each pair and then shielding the entire cable as well. IEEE 802.3 adds a fifth pair but I don't know if anyone uses it yet. Anyone seen it? -- 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