5-1
Section 5
RS-232 INTERFACE
5.1 GENERAL
Virtually all functions available through the keypad are also available through the RS-232
interface. Each command available over the RS-232 interface is included in Section 7 and is
provided with a description, normal syntax and usage, and both computer and terminal
communication examples. There are basically two types of commands available; one for
input, one for output. Input commands consist of the basic command word, followed by a
question mark (?), and are used to input information from the 5A-1MP to the computer or
terminal.
Output commands consist of the basic command word, followed by an equals sign (=), and
the numeric or string data, and are used to output information from the terminal or computer
to the 5A-1MP. Spaces are completely ignored by the 5A-1MP and are neither
acknowledged nor echoed. Errors in command syntax do not generate error messages. The
command in error is simply ignored.
For wiring/cabling instructions, refer to Section 2.3.
5.2
RS-232 PROTOCOL
All commands and data sent to and from the 5A-1MP are done so at the following factory
preset parameters:
Baud Rate:
1200 (Factory selectable from 300-9600)
Word Size:
8 Bits
Stop Bits:
1
Parity:
None
The 5A-1MP only requires one stop bit when receiving, but will use two stop bits while
sending. The computer terminal may be set to either one or two stop bits, depending on
user preference.
5.3 INITIALIZING THE HOST TERMINAL OR COMPUTER
Ensure that a computer/terminal is connected in accordance with Section 2.3. In order to
communicate over the RS-232 interface, the terminal or computer must be configured to
operate with the same protocol as that of the 5A-1MP. For the proper protocol parameters,
refer to Section 5.2, RS-232 Protocol.
The following example illustrates the initialization for IBM BASICA when the 5A-1MP
interface is connected to com1 of the computer.
