🚀 go-pugleaf

In article <1992Dec15.202004.15878@ucsu.Colorado.EDU> barr@tramp.Colorado.EDU (BARR DOUG) writes:
>Some specs I have call for ethernet coax to be grounded in one location
>and one location only! I am wondering why this is. Antenna effects,
>current loops or something else. Does anyone know why this is the case?

Current loops can cause I*R drops resulting in severe interference from
the AC power network.  The interference level may exceed that of the signal
by several Bels (=orders of magnitude).

I remember dealing with a shielded RS-232 cable that was forming a current
current loop between two otherwise disjoint power networks.  The cable
had become so hot that its plastic insulation would have melted had I not
noticed in time.  I noticed it because the data was corrupted beyond
any recognition, and the terminal would not work even at 50 bits/second !
Ethernet signals would be much more sensitive to such interference
with their smaller amplitude and higher speeds.
-- 
Mustafa Kocaturk   mustafa@seas.smu.edu  EE Dept., Room 305A, Caruth Bldg.
Home: 214-706-5954  Office: 214-768-1475  SMU Box 753190, Dallas, TX 75275