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.
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.
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.
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