Re: 56K on PM2e

Tom Samplonius (tom@sdf.com)
Tue, 17 Dec 1996 11:38:17 -0800 (PST)

On Tue, 17 Dec 1996, Erik R. Leo wrote:

>
>
> You need an *asynch* DSU/CSU (same unit on each end of the
> connection). We've used the Adtran 5600. The performance is about 75-80%
> of a 56K synchronous connection.
>
> -Erik
> --
> Erik R. Leo, Net Worker SoVerNet
> Tel: +1(802)463-2111 Vermont's Sovereign Internet Connection
> Fax: +1(802)463-2110 5 Rockingham Street
> Email: erikl@sover.net Bellows Falls, Vermont 05101
>
> On Tue, 17 Dec 1996, Scott A. Lagos wrote:
>
> > Can anyone recommend a low-cost 56K DSU/CSU that we could use to connect a
> > 56K DDS circuit to anyone of the Sx ports on a PM2e. In most cases we use
> > a Micro 900i and a Motorola DSU/CSU but seeing as we have spare ports on the
> > PM2e we figure we can save the cost of the router. I expect that almost any
> > DSU/CSU will work, but I would like to know of one that has few or no
> > compatibility issues with the PM2.
> >
> > Thanks
> >
> > Scott
> >
>

But Scott is using a DDS circuit, not a leased line, right? The 5600 is
a DSU for 56k leased lines I believe?

DDS lines have dial-tone. You will need something like an Motorola
DU56 (dial-unit), capable of v25bis dialing. I believe the DU56 can have
an RS232 async interface card installed.

Running async into a sync device doesn't need to have a performance
penatly, as long as the the device has buffering, can do hardware flow
control on the async serial, and can handle a async port speed of 115200.
The Adtran 5600 can only handle a maximum of 57600 on the async serial
port, which is just not enough to saturate a 56K sync line.

Tom