On Tue, 13 Feb 2001 at 11:01:05, Dent Jonathan
<[EMAIL PROTECTED]> wrote:
(Ref: <[EMAIL PROTECTED]>)
>Thank you Tony for taking time to comment on my article.
>
>-----Original Message-----
>From: Tony Firshman [mailto:[EMAIL PROTECTED]]
>Sent: 13 February 2001 00:29
>To: [EMAIL PROTECTED]
>Subject: [ql-users] QL Toady
>
>
>>Jonathan Dent's article in QL Toady Vol 5 Issue 5 needs comment too,
>>over and above saying that it is potentially the most important software
>>since QPAC2 and pointer environment.
>>
>>He says the QL cannot control data flow from the modem to QL.
>>
>>
>>
>>It always could, right from day 1.
>
>Only if the modem will let it. It maybe that certain modems have a
>limited buffer now but that was certainly unusual at day 1.
The Astracom had 2k in and 6k out. It was designed specifically to cope
with the basic QL, and because of the input buffer and sending 2 stop
bits, it worked fine with an unmodified QL.
Life has changed - it cost about £200 for V23 (1200/75) and almost £330
for 2400!
> The point
>is that a proper V.24/V.28 or RS232 data terminal equipment (DTE) interface
>should not require the data flow from the modem to be controlled. Data flow
>from the remote DTE can be controlled at a higher protocol level (e.g. by
>x-off, x-on), when buffers are getting full. In my experience superHermes
>fulfils this requirement.
It probably can but I use RTS.
>
>>
>>If SER2 DTR is connected to the modem RTS, then it will control flow
>>from the modem to QL. The QLs 'DTR' is in fact more correctly described
>>as 'RTS'
>>
>>SER2 CTS lines on both QL and modem connected together gives the output
>>control from QL to modem.
>>
>>The modem though can only store a limited amount of incoming data and
>>when this buffer is full, then incoming data _will_ be lost if it cannot
>>be sent to the computer.
>>
>>The point of RTS is to temporarily stop input if the computer is busy.
>>The 8049 does this job on the QL. The original 8049 on the QL often did
>>not do this correctly. For instance if it was generating sound, it
>>would 'forget' to set RTS. If data arrived in the 8049, and it was
>>unable to deal send them to the 8302, then the pointers to next data got
>>out of step. Only a full power down could correct this fault, as QL
>>'reset' does not reset the 8049. Hermes corrected this problem, and
>>allowed an incoming baud rate of 19200. Actual incoming data rate
>>depends on processor speed and current tasks, but can be up to about
>>12500bps.
>>
>RTS (request to send) is "normally" (V.24) used to turn on the transmit
>function;
>mainly useful for half duplex communication. I don't exclude the possibility
>that certain modems can use it differently, in fact I would be very pleased
>to find that this is the case. Can you tell me what modem can work like you
>describe (and perhaps the AT command required). If a modem can be persuaded
>to work like that I think soql could be used with a pretty basic black-box
>QL.
All the modems I have used with the QL in the last 15 years (8-)#
The little Miracle boxes did.
It started with the Astracom which I used and sold. It had a very
useful 2k input buffer for the standard QL and one could not turn off
RTS control with software (cut the wire!)
The next was a US Robotics Courier. This had a command summary printed
on the modem - why doesn't everyone do that? RTS had to be enabled (&R2
or by DIP switches).
The third I forget the name of, and it has long gone. That again needed
RTS enabled (default off).
The fourth in current use is USR V90 voicemodem. &R2 sets RTS control -
but it is the default.
I have also seen other modem manuals and they have all had RTS control,
although some needed it enabled.
>>He also says superHermes gives 9600 from ser2. What he should have said
>>was superHermes (including sH LITE) gives up to a full 19200bps incoming
>>throughput on both SER1 and SER2. The original QL has always had
>>19200 output via the 8302.
>>
>>
>I DO recommend swapping to sH LITE in a black-box or a full sH for a
>re-housed
>QL.
Thanks (8-)#
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