We use MICOM's Installink/460 data over voice encoder units (DOVE). They
allow you to use the same telephone line for concurrent data transmission.
They are similar to a modem using a different frequency for the data . We
have buildings over 2000 feet away from the DTCs with lots of terminals and
no problems. It may be a little expensive per connection, but it is trouble
free and wherever there is an extension, you can connect a terminal or a
printer.
 
The other option is to setup a modem pool to the DTCs but then you need
enough spare extensions and modems as the maximum number of concurrent
connections you want to allow. We also have one of those but mostly because
many users already with modems on their PCs can now share DTC ports through
it.
 
As others have already stated, the distance on a direct connection only
depends on the cable quality. I've had serial printers at distances over 400
ft without any problem.
 
Hope this helps.
 
[log in to unmask]
 ----------
>From: Dave Trottier (John Abbott College)
>To: lopezrod; Multiple recipients of list HP3000-L
>Subject: Terminal Communications
>Date: Tue, Sep 12, 1995 1:34PM
>
>
>We're seeking advice from folks who may have migrated from
>classics to ix machines but have retained RS-232 connectivity
>between their terminals and DTC's.
>
>We are in the process of migrating from a series 70 to a 928. On
>the 70 we were able to run terminals, using twisted pairs, over
>extensive distances of 500-800 ft. This was at 9600 baud without
>any multiplexors or line drivers.
>
>My understanding from the response center is that voltage on the
>ports (DTC72 with RJ45 interfaces) is less than that on the classic.
>Regardless, we know we're exceeding the RS-232 50 foot "limitation".
>
>Does anyone know of a quick method of remedying this problem; i.e.,
>of amplifying our signals so we may continue to use twisted pairs
>at thes distances? We are considering line drivers or muxes but are
>looking for the easiest practical solution (i.e., we don't want to
>move our DTC's from the Computer Room and start installing fibre
>optic cables, etc.).
>
>If you have any suggestions, please contact me at your convenience.
>
>Dave Trottier, Operations Manager, John Abbott College
>[log in to unmask]  or  (514) 457-6610, Ext. 206
>