Re: Phone Line Interfacing - FCC Part-68

On May 25, 2:36 am, "Michael A. Terrell" <mike.terr...@xxxxxxxxxxxxx>
wrote:
Were do they still use that much areial cable? Around here most telco
plant is underground, and fiber optic.

Let's see. Verizon only started to install FIOS a few years ago.
Most every wire connecting to the CO is copper. And for 100 years,
direct lightning strikes to that copper resulted in no damage when a
protector was properly earthed where it enter the building. Michael A
Terrell does not deny this reality.

FCC Part 68 requires this properly earthed protector at both ends of
a phone line. What makes a protector so effective? A protector is
only as effective as its earth ground.. No protector stops, blocks,
or absorbs the typically destructive surge. A protector that earths
before those surges can enter a building means protection inside a
modem is not overwhelmed. That was known even 100 years ago.

Two 'top of the front page' articles in Electrical Engineering Times
define what provides protection in "Protecting Electrical Devices from
Lightning Transients". Not a protector circuit. Protection is only
as effective as its earth ground and connection to earth ground. How
curious. Even FCC Part 68 requires a shorter connection to earth -
contradicting what Michael posts.

mpm - more could be learned. Not yet posted because engineering
questions are not being asked.

Makes little difference whether underground or overhead (Michael
ignores this reality only to argue). Same protection was required as
has been routine in telcos for 100 years to avoid surge damage.
.