romeo@lindy.Stanford.EDU (Patrick Goebel) (03/20/90)
Due to limited conduit capacity, it has been suggested to us that we pull 26 AWG unshielded twisted pair (UTP) to support a planned 10BaseT ethernet instead of the standard 24 AWG wire. I have heard that one can use either 22, 24 or 26 AWG wire with only a corresponding reduction in the length of the maximum run. However, I am concerned that there might be additional electrical differences that could cause the 22 and 26 AWG media to fall outside the 10BaseT specs. Does anyone know if the current form of the 10BaseT "standard" specifies only a 24 AWG medium? Many thanks, patrick goebel--romeo@lindy.stanford.edu
macklin@garnet.berkeley.edu (Macklin Burnham) (03/21/90)
In article <8564@lindy.Stanford.EDU> romeo@lindy.UUCP (Patrick Goebel) writes: >Due to limited conduit capacity, it has been suggested to us that we >pull 26 AWG unshielded twisted pair (UTP) to support a planned 10BaseT >ethernet instead of the standard 24 AWG wire. I have heard that one >can use either 22, 24 or 26 AWG wire with only a corresponding >reduction in the length of the maximum run. However, I am concerned >that there might be additional electrical differences that could cause >the 22 and 26 AWG media to fall outside the 10BaseT specs. Does >anyone know if the current form of the 10BaseT "standard" specifies >only a 24 AWG medium? > The standard specifies 22-26 AWG wire, with no distance penalty.The equipment is supposed to drive 100 meters of wire of any of those sizes. Mack Burnham ~
dls@mtunh.ATT.COM (Dinah Sloan) (03/21/90)
In article <1990Mar20.163348.6033@agate.berkeley.edu>, macklin@garnet.berkeley.edu (Macklin Burnham) writes: > In article <8564@lindy.Stanford.EDU> romeo@lindy.UUCP (Patrick Goebel) writes: > > <question about using 26 AWG UTP wire vs. 22 or 24.> > >Does anyone know if the current form of the 10BaseT "standard" specifies > >only a 24 AWG medium? > > > The standard specifies 22-26 AWG wire, with no distance penalty.The equipment > is supposed to drive 100 meters of wire of any of those sizes. Actually Draft 10 of the proposed standard, section 14.4 is relevant to this question. It states requirements for insertion loss, delay, differential characteristic impedance, jitter, NEXT (near-end crosstalk), etc. It also states in 14.4.2 that "These characteristics are generally met by 100m of unshielded twisted-pair cable composed of 24 AWG twisted pairs." Past experience has led me to answer the question "will this cable work" with a request for a copy of the characteristics of the cable. Choosing cable of a particular guage only tells you a small part of the story. If you need more specifics, get a hold of the draft standard. (Of course, if that fails, you can always try contacting me and I'll try to answer your questions.) Dinah Sloan att!mtunh!dls AT&T Bell Laboratories 200 Laurel Ave. Middletown, NJ 07748
ncpjmw@pepsi.amd.com (Mike Wincn) (03/22/90)
In article <8564@lindy.Stanford.EDU> romeo@lindy.UUCP (Patrick Goebel) writes: >the 22 and 26 AWG media to fall outside the 10BaseT specs. Does >anyone know if the current form of the 10BaseT "standard" specifies >only a 24 AWG medium? > >Many thanks, >patrick goebel--romeo@lindy.stanford.edu Draft 10, as well as earlier drafts, focuses on 24 gauge UTP, but makes allowances for 22 to 26 gauge wire. The reasons for primary focus on 24 GA included that there was a great deal more information available on the use of that wire size in that noisy environment, that the 10Base-T task force didn't have the resources to do full investigations of all other gauges, and that a need for writing such a weighty tome was never established. An end user is not restricted to 24 GA UTP. Draft 10 stipulates that an end user is free to use any wire gauge, or combination of wire gauges, that he chooses as long as it can be shown that a given link segment does not exceed limits on attenuation, delay, line impedance, or crosstalk, and only then if he intends to transmit over a distance of at least 100m. It is presumed that an end user who chooses to work with a system that exceeds Draft limits will then accept responsibility for non-compliance. Mike Wincn (408) 749-3156 ncpjmw@pepsi.AMD.COM Opinions expressed are my own, not necessarily those of AMD or the 10Base-T Task Force.