Download User Manual - EndRun Technologies

"Smarter Timing Solutions"
ChapterThree
Control and Status Commands
This chapter will describes the ASCII protocol supported by the Praecis II. For the RS-232 serial I/O
port physical and electrical characteristics see Appendix D - Specifications.
General Serial I/O
Operation
The Praecis II commands are NOT case sensitive. It accepts input commands that are terminated
with either an ASCII Carriage Return (CTRL-M, 0x0A) control character (denoted by <CR>) or an
ASCII Carriage Return (CTRL-M, 0x0A) - Line Feed (CTRL-J, 0x0D) pair of control characters
(denoted by <CR><LF>). The Praecis II terminates all status messages that it sends in response to
commands with a <CR><LF> pair. The Praecis II does not ‘echo’ any user input.
The Praecis II responds to invalid commands with:
ERROR<CR><LF>
or
INVALID OPERATION<CR><LF>
At power-up with factory default settings, the Praecis II outputs a time-of-day message once-per-second. The factory default emulation mode is NONE, and the Praecis II sends the time-of-day message
in its native EndRun format. See Chapter 4 - Time-Of-Day Messages for details on the various clock
emulation message formats.
RECOMMENDED TERMINAL SETUP
Use ANSI terminal emulation mode and turn OFF handshaking.
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Praecis II User Manual