DB>Robert Osborne wrote in a message to Rick Collins/All:
DB> RO> What about externals?  How are they configured for comm port and
DB> RO> IRQ.  I see several used modems for sale, both internal and
DB> RO> external.  Most do not have documentation with them as to how to
DB> RO> configure.
DB>An external modem does not have to configure for comm port
DB>and IRQ.  All they have is an RS-232 port.  The comm port
DB>internal to your computer must be configured but that has
DB>nothing to do with an external modem's configuration.
OK I have that straight now! They are hooked serial to the
computer right?   Lets talk a little bit more about I/O ports on the
computer.  You have Com 1 thru 4 and LPT1 & 2 usually.  I always thought
that Com ports were serial and LPT1 being to a printer were Parallel?
As I remember you can redirect a parallel port to a serial port correct?
Now the trick is to understand what you have hooked to what and to get
the right Interupt Request set so that there is no conflicts as to
different equipment hooked up to each port.  A mouse is serial and I
have it hooked to Com1.  I'm not sure what exactly the address has to do
with it but I though the Irq established/ sets the pecking order as to
which gets serviced and in what order by the CPU? Feel free to expand
and correct on this?
DB> RO> I also thought that there is some limiting speed over the
DB> RO> communication media being used.  Ie 28.8 was the upper limit for
DB> RO> telephone lines? Maybe higher for cable lines or fiber optic.  Is
DB> RO> it also not true that the newer modems don't really transmit at
DB> RO> higher rates, but instead compress and decompress the data on the
DB> RO> fly to obtain faster rates of data thru put?  When did they start
DB> RO> all this and at what modem speed did compression take place?
DB>Not quite right.  A modem can transmit uncompressed data at
DB>speeds up to 33,600 bidirectionally and up to 56K in one
DB>direction using either x2 or K56Flex.  The data compression
DB>and error correction add on to those speeds -- you could
DB>purchase a 2400bps modem with error correction and data
DB>compression though I haven't seen one for sale in a few
DB>years.
Ok but please explain x2 and k56Flex?  Are they in common use today for
private individuals or just special equipment for commercial use?
Thank you for your reply and the Info.
Robert Osborne
1:346/49
Internet: Robert.Osborne@Tesla.circuit.com
 * OLX 2.1 TD * I'M DOING BETTER, I'VE ONLY MALFUNCTIONED ONCE TODAY!
--- Maximus/2 3.01
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