Product manual

XStream‐PKG‐R™RS‐232/485RFModem–ProductManualv4.2B
©2005MaxStream,Inc.Confidential&Proprietary   17
3.2.5. Command Mode
To modify or read modem parameters, the modem must first enter into Command Mode, the
state in which incoming characters are interpreted as commands. Two command types are
available for programming the modem:
• AT Commands
• Binary Commands
For modified parameter values to persist in the modem registry, changes must be saved to non-
volatile memory using WR (Write) Command. Otherwise, parameters are restored to previously
saved values when the modem is powered off and then on again.
AT Commands
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 X-CTU Software can be used
to enter the sequence.
[OR]
2. Assert (low) the pin and turn the power going to the modem off and back on. This
result can be achieved by keeping the configuration switch pressed while turning off, then on
again the power supplying the RF Modem)
Default AT Command Mode Sequence (for transition to Command Mode):
• No characters sent for one second [refer to BT (Guard Time Before) Command]
• Input three plus characters (“+++”) within one second [refer to CC (Command Sequence
Character) Command.]
• No characters sent for one second [refer to AT (Guard Time After) Command.]
To Send AT Commands:
Send AT commands and parameters using the syntax shown below:
Figure3.8. SyntaxforsendingATCommands
NOTE: To read a parameter value stored in a register, leave the parameter field blank.
The preceding example would change the modem Destination Address to “1F”. To store the new
value to non-volatile (long term) memory, the Write (ATWR) Command must follow.
System Response. When a command is sent to the modem, the modem will parse and execute
the command. Upon successful execution of a command, the modem returns an “OK” message. If
execution of a command results in an error, the modem returns an “ERROR” message.
To Exit AT Command Mode:
1. Send ATCN (Exit Command Mode) Command.
[OR]
2. If no valid AT Commands are received within the time specified by CT (Command Mode
Timeout) Command, the Modem automatically returns to Idle Mode.
For examples that illustrate the steps of programming the modem using AT Commands, refer to
the Modem Configuration [p19] chapter.