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Cell Relay Retreat>List Archive>month:1998-Jul> msg00246



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Re: Optical vs. Electrical Interfaces

  • From: James Carlson <carlson@ironbridgenetworks.com>
  • Date: 21 Jul 1998 09:49:26 -0400

Fahad A Hoymany <fahad@judy.cs.pitt.edu> writes:
>         Our network provider says they cannot provide us with an optical
> interface to their network.  They can only give us an E3 electrical
> interface.

Maybe STM-1/STSX3?  E3 is a european PDH standard.

> 1. Does it matter if you use electrical or optical STM-1 interface?

They're equivalent in terms of the data formats.  Obviously, though,
you can't plug one directly into the other.

> 2. If they give us an electrical interface to their network, does that mean
> the actual signal over the fiber link (into their network) is electrical?
> Is it even possible that an electrical signal be carried over a fiber line?

Uh, not exactly.  The fibers aren't conductive.  It's entirely
possible, though, to mux an electrical signal onto a fiber, and the
telco is probably doing this.  (75 ohm coax drops are probably cheaper
for them ...)

-- 
James Carlson, Consulting S/W Engineer  <carlson@ironbridgenetworks.com>
IronBridge Networks / 55 Hayden Avenue  71.246W    Vox:  +1 781 402 8032
Lexington MA  02421-7996 / USA          42.423N    Fax:  +1 781 402 8092
"PPP Design and Debugging" --- http://people.ne.mediaone.net/carlson/ppp