Technical information

Aterm Serial Solutions
digit keys to make a selection. The menus include setting the
port, the Baud rate, the number of data bits, the number of stop
bits and the parity.
F10 Quit. This immediately exits the program.
ALT-C (That is ’C’ and the ’ALT’ key pressed together).
Aterm prompts the user for a command. The user can enter a
command together with any parameters that it requires. These
are the same commands found in the definition files, and control
the way that the terminal functions.
Translations.____________
Aterm has the ability to translate any characters read from
the serial port or the keyboard to a sequence of zero, one or
more characters. The chapter "Terminal Emulators" discusses this
in more detail. Note the following: When Aterm translates
characters received form the serial port it uses a null character
(value 0) to mark the end of the sequence. This means that a
null cannot be included as part of an input translation. Since null
cannot be displayed this does not greatly matter for general use.
Nulls can be included in output translations and can be
transmitted with the T command.
The ATERM Serial Connection.____________________________
This section will look at the parts of ATERM that access
the serial port and so explain how any assembly language
program could use the serial port with NewCOM. The use of the
serial port is quite straight forward, as NewCOM does most of
the hard work.
Quick Summary._______________
From assembly language use DOS functions through INT
21H to access the serial port. The functions used by Aterm are
as follows.
Function 3DH, open handle, to open a file to the serial port;
Function 3FH, read handle, to read characters from the port,
Chapter 8 Page 129