Hello Coridon!
10 Mar 98 14:17, Coridon Henshaw wrote to Hans Mangold:
 CH>>> They also have one big disadvantage: the parallel port does not
 CH>>> carry a FIFO, meaning that it will generate up to sixteen times
 CH>>> more interrupts at a given data rate when compared to a serial
 CH>>> modem on a 16550.
 HM>> You sure about that???  My LPT2 does indeed have a 83-byte FIFO.
 CH> I wouldn't be surprised if EPP and/or ECP are buffered, but a standard
 CH> parallel port contains no buffering.
 CH> What kind of port hardware is it?
It's a SIIG "HighSpeed/Hi-IRQ I/O" I/O Expander 3P (for up to 3 par. ports), 
Model # IO1814.  While it makes no mention anywhere in the (otherwise 
=excellent=) manual of ECP or EPP, Win95 identifies it as ECP.  However, at 
the same time, Win95 does not assign a DMA, so I'm tempted to believe that it 
is in fact EPP!  :-)
Be that as it may, SIIG refers to it simply as "Bi-directional Port", we can 
be sure it's one or the other, ECP/EPP. :-)
The main reason why I selected this card was that it offers the most 
flexibility in terms of IRQ selection: 3, 4, 5, 7, 9, 10, 11, 12 & 15 -- only 
to discover _later_ that my tape drive is restricted to 5 or 7.  :-(  At 
present, I have my Zip drive connected to LPT1 and a TR1 tape drive to LPT2 
(the I/O card); my HP 5L in turn is connected to the pass-through connector 
of the tape drive.
The card comes with one port; up to two additional ports can be installed 
with upgrade kits consisting of a chip and connectors.
Unfortunately, none of my equipment is really suitable for measuring any 
performance differences, i.e. my Zip drive & tape drive yield pretty well the 
same results on this I/O card as on the motherboard's (Asus TX97x) LPT1, in 
either ECP mode (with DMA) or EPP mode.
To get back on topic, if I could get my hands on a parallel modem for a day 
or two, I'm sure I'd be able to test the 83-byte FIFO on the I/O card!  
Mind you, much of this is academic; USB modems are already in stores (USR 
Sportster) and, much to my surprise, they are indeed selling, despite the 
Can$100 (US$140) premium over equivalent, conventional external modems. 
Hopefully, once Win98 is introduced, demand for USB modems will increase, 
pushing the price down to where even I can afford to buy one. 
Cheers, Hans
... Hell knows no fury like a pissed off SysOp.
--- GoldED/386 2.50+ / Binkley32 / Maximus / Squish / WINDOWS 95 / V34+
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