So, the FXS or FXO port on the router is labeled from the perspective of
the device that connects to it?  In other words, a station connects to
an FXS port?  And a PBX connects to an FXO port?

This would be the opposite perspective from what they use when
labelling their cabling, which is always from the perspective of the
router.

This is all very confusing.  :-(  Either I'm continually
misunderstanding the examples or several of us have a major
misunderstanding when it comes to this stuff.  Neither situation is
good.

John

>>> "Bruce Enders"  9/27/02 12:23:28 PM >>>
The simplest way I know of to explain these is to take the last letter
(O or S) and associate that to where it will connect TO. So, an FXO
connects to an Office (PBX or CO) and an FXS connects to a Station
device
(Telephone, Fax, or answering machine).
As Chuck suggests, if you are connecting from an "O" it will connect
to
an "S", and vice versa, just like DTE and DCE. (Remembering it this
way
comes in handy when you are connecting two PBXs, or PBX to CO, or
voice
gateway to PBX or CO). OBTW, that voice gateway is a microscopic size
PBX.
Bruce

 Chuck's Long Road wrote:

  I did some quick looks into a couple of books I have to see what they
say.
  
  Scott Keagy's book "Integrating Voice and Data Networks" has nothing
to say
  about FXO and FXS in particular.
  
  The "Cisco Call Manager Fundamentals" book makes the rather brief
assertion
  that "FXS ports provide connection to loop-start or ground-start
telephone
  lines, ...  ( PBX ) ports, and other analogue telephone devices. FXO
ports
  provide connection to central office ports or PBX extensions"
  
  Interesting wording, and seems to apply to what I was told.
  
  Learn something new, some better way to think about things, every
day.
  
  Chuck

  ""Jennifer Mellone""  wrote in message 
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]  ...

    That sounds great and makes more sense now! I always like reading
your

  posts

    :-)
    
    I always confuse which device plugs into which port. I remember it
like

  this:

    Plug phone or "Station" into FXS (where Station=S)
    Plug PBX/CO into FXO (where Office=0)
    
    - Jennifer
-- 

  Bruce Enders                       Email: [EMAIL PROTECTED] 
Chesapeake NetCraftsmen            o:(410)-757-3050, c:(443)-994-0678
  1290 Bay Dale Drive, Suite 312     WWW: http://www.netcraftsmen.net 
Arnold, MD 21012-2325              Cisco CCSI# 96047
                                     Efax 443-331-0651




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