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 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.
>
>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.
>
>
>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.
Jon.
--
QBBS (QL fido BBS 2:257/67) +44(0)1442-828255
mailto:[EMAIL PROTECTED] http://www.firshman.demon.co.uk
Voice: +44(0)1442-828254 Fax: +44(0)1442-828255
TF Services, 29 Longfield Road, TRING, Herts, HP23 4DG
