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Modes of operation
9XTend-PKG-R RS-232/485 RF Modem User Guide
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Each RF transmission consists of an RF Initializer and payload. The RF initializer contains initialization information
and all receiving modems must wake during the wake-up initializer portion of data transmission in order to be
synchronized with the transmitting modem and receive the data.
The cyclic interval time defined by the SM (Sleep Mode) command must be shorter than the interval time defined by
LH (Wake-up Initializer Timer) command.
The following figure shows the Correct Configuration (LH > SM):
The length of the wake-up initializer exceeds the time interval of Cyclic Sleep. The receiver is guaranteed to detect the
wake-up initializer and receive the accompanying payload data.
Command mode
To modify or read modem parameters, the modem must first enter into Command Mode (state in which incoming
characters are interpreted as commands). Two command types are supported:
•
AT Commands
•
Binary Commands
For modified parameter values to persist in the modem registry, changes must be saved to non-volatile memory using
the WR (Write) command. Otherwise, parameters are restored to previously saved values when the modem is
powered off and then on again.
AT Command mode
To Enter AT Command mode:
1. Send the 3-character command sequence "+++" and observe guard times before and after the command
characters. [refer to ‘Default AT Command Mode Sequence’ below.] The ‘Terminal’ tab (or other serial
communications software) of the XCTU Software can be used to enter the sequence.
[OR]
2. Assert (low) the CONFIG pin and turn the power going to the modem off and back on (or pulse the SHDN pin).
[If the modem is mounted to a Digi RS-232/485 Interface Board, the result can be achieved by pressing the
configuration switch down for 2 seconds.]
Default AT Command Mode Sequence (for transition to Command Mode):
•
No characters sent for one second [refer to the BT (Guard Time Before) Command]
•
Input three plus characters (“+++”) within one second
[refer to the CC (Command Sequence Character) Command.]
•
No characters sent for one second [refer to the AT (Guard Time After) Command.]
All of the parameter values in the sequence can be modified to reflect user preferences.