Before ISP's and Internet Cafes,
remote access meant using a serial modem to dial another modem
connected to the serial port on a computer. Initially, there
were no PC's involved. A terminal would be connected to the
modem with a serial cable and the modem would be connected
to its counterpart with the public telephone lines or a leased
line. The serial speeds which early modems were able to achieve
were underwhelming. Typically they were 4 to 16 times slower
than what the user experienced at the computer site. The first
modems lacked error control or correction making them less
usable on bad telephone lines. And to make matters worse,
they were expensive, anywhere from $500 to $2,000.
But the world was not going to be
forced to stay in its office and the demand for modems drove
the industry to produce higher quality modems for less money.
Bit by bit, (no pun intended,) all the shortcomings were eliminated.
New modem communication protocols allowed the serial speed
to be increased to that used in the office and made remote
work on terminals more efficient. The new protocols provided
error checking which allowed modems to be used on bad telephone
lines without the usual and frequent interruption due to disconnection.
And the $2,000 modem was reduced in cost to less than a hundred
The serial speed of modem connections
is determined by the modem communication protocols supported
by the modem and the quality of the telephone line. The modem
communication protocol is the software that the modems use
to talk to each other. The software is written and saved on
a chip in the modem so it would be more accurately called,
firmware. The better the software, the faster the modem can
transmit and receive data. The electronic hardware components
must also be good to transmit and receive data fast but the
entire package must be matched so the package is represented
as a modem protocol. The protocols typically have names like
V.32, V.42, V.90.
Now days modems are comparatively
cheap and it would be a waste of energy to use less than a
V.32 protocol modem, at 9600 baud for serial terminal use.
Indeed, any less speedy modem is probably not in use today.
The much faster, V.90 modem protocol, is supported on 100%
of modems sold today. With data transfer rates of up to 56K,
it more than adequately supports serial terminal communications
and is more commonly used for network communications.
Typically, modems are downward compatible
in protocol so if you have a V.90 modem you will have no problem
connecting to any other modem even if it is old and doesn't
support the V.90 protocol. And as long as both of the modems
are V.32 or better, a serial connection can be made at a baud
rate sufficient for serial terminal use. Similarly, if you
are forced to use an older modem, as long as it supports,
at least the V.32 modem protocol, it will be fast enough for
fast serial communication and it will also connection to higher
speed modems which will be downward compatible.