Re: gEDA-user: Building the PCB+GL branch [WAS: Re: Open GL survey (for PCB)]

[msokolov@xxxxxxxxxxxxxxx (Michael Sokolov)]

DJ Delorie <dj@xxxxxxxxxxx> wrote:

> Actually, four wires all the way out the driveway.  I know it's not
> the two-wire variety because the last time they had to fix it, they
> commented on the fact that I hadn't been "upgraded" to the two-wire
> one.  I have two lightning protectors in the demarc box, not one.  And
> yes, it usually throws off the repair guys.

Hmm.  The fact that you have a "smartjack" demark at all (do you?)
suggests to me that it's still an HDSL terminal, albeit the older 4-wire
HDSL1 variety.  It's still 4 wires like a Classic T1, but instead of
each pair carrying 1.544 Mbps in one direction only, each pair carries
1/2 of the T1 in both directions.  The smartjack unit has two RS8973 or
Bt8970 chips in it, each driving one HDSL pair, an 8953 chip combining
them together into the full T1 frame, and whatever other chip is the PHY
for the T1 interface presented to the user.

On-topic bit for this list: I have gschem symbols for RS8973 -- that's
the chip that was taken out of the HDSL system described above and used
by itself to make what's called SDSL.

MS


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