1257 User Manual
Computer Interfaces 4-22
EADS North America Defense
Test and Services, Inc.
©
2001
terminator, then no action is necessary. Otherwise, press the
fourth key. Rotate the knob until the desired EOL terminator
shows on line 4. In this example, “CR/LF” is desired:
-----SETTINGS-----
Type: RS-232
Option: Baud Rate
<Update?: CR/LF
Then press the fourth key to confirm the update. Pressing any
other button cancels the change.
When using a data terminal, or a computer with terminal-emulation
software, it is recommended that you set the 1257 to use the
CR-only terminator. In this case, also set the data terminal or
computer to half-duplex operation (local echo), with line feed
appended to incoming messages (see your data terminal manual
for information on how to do this).
NOTE:
Menu preferences are not normally retained after the power is
removed from the instrument. To make (a) menu preference(s)
permanent, make the desired change(s) to settings first and
then proceed to the section Storing the Menu Preferences to
make the changes permanent. Following this procedure will
put the settings into non-volatile memory and allow them to
be restored during instrument power-up.
Setting the
Data Bits,
Stop Bits, and
Parity
The 1257 allows the user to set the following additional RS-232
parameters:
•
Data bits:
Data bits per frame. The RS-232 interface allows
either 7 or 8 bits per data frame. For most applications, set this
to 8.
•
Stop bits:
Stop bits at end of each frame. The RS-232
interface can insert either one or two stop bits at the end of
each data frame. Slow data terminals may require the extra
delay resulting from two stop bits. However, for most
applications, one stop bit is sufficient.
•
Parity:
Type of parity checking. Parity checking provides a
level of confidence that data has been received properly. When
parity checking is used, an extra bit (the parity bit), is inserted
at the end of each data frame. The RS-232 interface provides
three parity options: “none” (no checking performed), “even”
(sum of all bits including parity bit is an even number or zero),
and “odd” (sum of all bits including parity is an odd number).
For most applications, this is set to “none”.
