bob@islenet.UUCP (Bob Cunningham) (08/20/86)
Digital, 3COM et al recommend RG58C/U for "thin wire" Ethernets. RG58C/U
various only slightly in construction from (the 70% more expensive) more
common RG58A/U. The major difference is that C/U has a "non-contaminating"
vinyl jacket...which apparently means that if it catches fire the fumes are
less harmful to humans.
Trying to decide which cable to buy in bulk, I came across another RG58A/U
type cable (trade/Belden number 8219) with a cellular (foamed) polyethylene
internal insulation and a higher velocity propagation (.78c instead of .66c
for regular RG58A/U and C/U). Curiously enough it seems to have exactly
the same electrical characteristics as regular "thick" Ethernet cable (same
capacitance and apparently same LC).
Assuming I don't need non-contaminating jacketed C/U, this looks like the
cable of choice for thin Ethernet.
Question: has anybody tried it? Are thinwire transceivers (e.g. 3COM
units) really tuned specifically for C/U-A/U cables, or is it reasonable to
suspect that 8219 is actually a better cable for thinwire applications?
--
Bob Cunningham {humu|ihnp4}!{islenet|uhmanoa}!bob
cunninghamr%haw.sdscnet@LLL-MFE.ARPA
Hawaii Institute of Geophysics, University of Hawaii