Re: TI-H: fargo fterm

Subject: Re: TI-H: fargo fterm
From: Mel Tsai <tsaimelv@pilot.msu.edu>
Date: Fri, 15 Nov 1996 14:51:27 GMT
In-Reply-To: <Pine.LNX.3.94.961115025223.13320A-100000@ticalc.org>
On Fri, 15 Nov 1996 03:01:00 -0500 (EST), you wrote:


>Fterm does *NOT* emulate RS232 with the link port. Fterm simply sends =
and
>recieves raw bytes from the link port. It is possible to hook the TI-92 =
to
>RS232 devices by using the TI GRAPH-LINK cable. This is the ~$50 grey
>cable with a large hood at the DB-25 connector. In this hood are
>complicated microelectronics which convert the TI's strange asynchronous
>protocol to standard RS232.


Actually, the TI *does* send emulate RS232.  The TI doesn't have any
"strange asynchronous protocol" and it doesn't send "raw bytes."
RS232 is simply a format by which bytes are sent, i.e. baud rate, stop
bits, parity, etc.  Fterm handles this for you.  What the Graph-Link
cable does is it converts the TTL voltages of the link port (+0V and
+5V) to RS232 voltage levels (-15V and +15V).  There's probably some
sort of MAX232 equivalent chip in the graph link cable. This
conversion can't be done with just a few simple passive components.
It requires a charge pump DC-DC converter, which is what the MAX232
does (like in the connect 85).  As long as the TI-92 can keep the baud
rates and bit format straight, it should be able to send/receive at
any baud rate up to 14.4, but currently fterm isn't sophisticated
enough to handle this.  In spite of this it may not be fast enough to
handle 14.4 rates without a FIFO buffer, and you'll probably get a
whole bunch of data overruns.


>Oh, and FTerm does not, repeat, DOES NOT provide VT100 emulation. It
>simply acts as a "dumb" terminal.=20


Are you sure about this?  Some other people said that it does (I
thought that someone was successfully using Lynx through their TI-92).


>In fact, it is possible to use Talk85 on
>the TI-85 as a terminal program in the same way as fterm on the TI-92.


Talk85 probably can't handle it.  Even if Talk85 used the ROM's send
routines to get exact flow rates of 9600, there would be no way of
sending certain characters and you couldn't handle full-duplex modes.
There's also other flow rate and data format issues that Talk85 can't
handle, so I doubt it will work.


-Mel
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