Ascend Archive
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Re: (ASCEND) APEX Rapid Transit modem
On Mon, 12 Jan 1998, Darkshot wrote:
> This is so weird. My neighbor just bought a machine from us-
> same machine as I have, same modem, same code rev on the modem,
> etc...and I live in the boonies and have never EVER gotten a
> K56-level connection and never expected to. However, my neigh-
> bor can, but ONLY when he dials our Durham PoP which is
> (1) Long Distance and (2) PRI. The local PoP is all CT1's and
> close to the CO have worked better than our PRI's in Durham.
Weird things happen in the wonderful world of telephone routing. Most
likely:
1) Your phone service is routed between you and the phone company CO over
an analog-type T1. Your neighbor's phone is probably on a different one
which goes to a different switch.
Someone smarter let me know if I'm making no sense. This is the way I
understand it. :)
2) There are many ways to connect switches together. It is likely that
the switch to which you dial in is connected to your PoP's switch via an
analog (sometimes called "universal") connection. These will destroy K56
connections no matter what. Most likely your PoP's switch is old and can
only handle such analog connections, therefore, anyone on that switch can
get good connections but anyone on a different switch gets bad
connections.
3) The switch to which your neighbor connects, is probably new and uses
digital connections between switches. Furthermore the switch to which
your remote PoP connects (using PRI's) is almost certainly newer and can
handle digital connections as well. Therefore, your neighbors' long
distance connection is all digital end to end except at his house, and
does not suffer degradation.
4) An extra K56-killing D/A - A/D conversion can happen anywhere and at
any time, for any or no reason. It happens more often on switches which
can't support PRI because often they don't support digital switch
interconnection either.
> When we first started with K56 (June 97) K56 wouldn't work at
> ALL via long distance. There's something here we need to know;
Probably your phone company changed some of the long-distance switch
interconnections from analog to digital, therefore allowing K56 over those
long distance connections.
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