[comp.protocols.tcp-ip] TCP/IP access to GEAC

SHERWOOD@AC.DAL.CA (John Sherwood) (04/15/89)

> They have their own funny terminals which talk some strange
>multidrop polling protocol to the GEAC over the async line.

Bob:

Our GEAC allows the asynch terminals to be configured as GLASS-TTY
instead of the multi-dropped polling type. This means you can connect
a single, dumb ASCII terminal to the GEAC port. Makes for an easy
connection to the terminal server, right?

Wrong. They neglect such frills as flow control and connection control.
We figured out (the hard way) that you can do the following:

) Flow control of data from the GEAC port can be controlled by toggling the
  DSR line (nobody can explain why this works; not even GEAC). Flow control in
  the other direction doesn't seem to be possible.

) GEAC will signal a disconnect by dropping DTR for about 2 seconds. After
  the 2 seconds it will assume it has a new session and start painting
  screens unless DSR is low.

) The server must signal disconnect to GEAC by sending the ASCII string "END".
  This has not proved to be bullet-proof and new users sometimes connect
  into the middle of someone else's session.

All this applies to the older 8000 series machines. Our 9000 is in and
running, but I haven't had a chance to see if things have improved. If
anyone has a better way of doing things, would we ever like to hear it!

Cheers

John Sherwood
Dalhousie University
Halifax, Nova Scotia