Apple IIgs - Manual (Page 50)

Page 50 of 84 II gs
Printed: Thursday, July 25, 2002 12:14:50 PM
Add LF After CR
Suppose you try printing something and you don't get any line feeds, the lines are printing on
top of each other and all you get is one line of typed smudge. Set the automatic line feed
switch on your printer to ON or use the Add LF After CR option to add an extra line feed after
each carriage return.
Echo
When you send a message through your modem, you can elect to have the message displayed on your
own screen as well as on the screen it's being sent to. This is called echo, and it's a nice
way to assure yourself that your message is being sent correctly. In most cases, you won't need
to select the Echo option because the com-puter you're sending the message to will probably
send an echo of the message to your screen as a way of confirming that it received your
message. If you select the Echo option and the other modem sends an echo, you'll be seeing
double.
A full-duplex modem will echo characters back to your monitor. A half-duplex modem won't. If
you're communicating with a full-duplex modem, set Echo to No. If you're communicating with a
half-duplex modem, set Echo to Yes. If you don't know what kind of modem is on the other end of
the phone line, select Yes. If you find everything coming through double, change to No. Most
information services, like CompuServe and The Source, use full-duplex modems.
Buffering
The buffer is a special holding area in RAM that holds information until the computer or
peripheral device is ready to deal with it. Don't change this setting unless the manual that
came with your device tells you to.
Baud
The Apple IIgs can send and receive information at a wide range of speeds from 50 bits per
second to 19,200 bits per second. The important thing is that the computer and the printer or
modem agree in advance on the speed that the bits will be traveling.
Bits per second (bps) is more commonly referred to as baud, which means rate of transmission.
The computer is more adaptable about baud than the device, so check what baud the device uses
and select the same speed for the computer by using the Baud option. You'll usually find baud
listed on a specifications page in the man-ual that came with your printer or modem. The most
common baud for modems is 1200. The most common baud for printers is 9600.
Data Bits/Stop Bits
The computer sends and receives each character of data out the serial port as a string of bits.
Characters can be represented with seven or eight data bits. It doesn't matter which you choose
as long as there is agreement between the computer and the device it's communicating with. The
most common data format is eight data bits. The manual that came with the device will indicate
what setting to use.
Stop bits are used to mark the end of each string of data bits. Some devices expect to receive
one stop bit; others expect to receive two.
Parity
Some devices expect to receive a parity bit, which is used by the receiving device to make sure
the data didn't get garbled during transmission. There are three parity options you can select:
odd parity, even parity, or no parity. Most devices don't use parity checking, so if you're