The unit will only respond to certain command strings:
Upper case characters are used for all commands
Spaces are echoed, but are ignored by the parser
Single character command
COMMANDS
Enter
Escape
?
ASCII
13
27
63
47
FUNCTION
processes the input buffer contents (and clears the buffer)
terminates setup mode and returns to normal 'data' operation
prints the current contents of the command buffer
(as above)
/
-
54
38
127
shortcut for the STATE command (see later)
shortcut for the RX command
clears the input buffer
&
delete
General commands
COMMANDS
DEFAULT
STATE
FUNCTION
The unit self-reprograms with ALL original factory preset values
Prints out the current operating parameters (a single minus sign, ascii 54, does the
same)
LOCK
EXIT
The unit now defaults to setup (rather than data) mode on power up
Return to data mode (same effect as an escape (ascii 27) byte)
If a LOCK command is in force, an escape byte has no effect, but EXIT overrides LOCK
Turns on the transmitter, and outputs a continuous 200Hz tone
This mode is disabled by any activity on the TXD input
Turn on the receiver/decoder (as if in data mode) and output received packets as
normal
This mode is disabled, and command mode re-entered, by any activity on the TXD input
TEST
RX
Baud rate commands
As supplied, the main interface is set to 4800 baud, and the auxiliary port to 2400 baud .
COMMANDS
BAUD b1
BAUX b2
FUNCTION
Set main port baud rate
set aux port baud rate
NOTES
b1, b2 are baud rates
Only the first two digits are needed, i.e. BAUD 12 is valid
Main port (b1) supports 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800
Aux port (b2) supports 1200, 2400, 4800, 9600 only
These setup parameters are immediately stored in E2PROM, and take effect right away. Remember that
baud rate scales with changes in crystal frequency (for example, if a 4.9152MHz crystal is fitted then BAUD
2400 will set a baud rate of 600).
When the interface baud rate is higher than the (4800 baud nominal) radio link interface speed, the system is
no longer truly transparent. As the modem is removing bytes from the buffer slower than the user interface is
supplying them, it is possible to over-fill the buffer and lose data, unless the user carefully controls the timing
of the data stream or uses the TX_flow signal.
This pin allows the status of the transmit buffer to be monitored. It begins low. It goes high when the buffer
reaches ¾ full, and is then re-set (to low) when the buffer is empty again.
It can be used to provide a simple 'CTS' signal.
[ It is possible to 'lose track' of the baud rate of a unit while manually programming it. In this case an easy
way of 'finding' the speed can be used: a byte should be sent to the device at each of the valid baud rates,
and the echoed character monitored. Only at the correct rate will a correct echo be seen ]
Timing commands
COMMANDS
DELAY dd
PREAM pp
TXOFF oo
FUNCTION
Set the initial delay between first byte arrival and transmit start (20mS default)
Set the number of (620uS long) preamble bits (80 its / 50mS default)
Set the tx ramp-down period (20mS default)
Note: Variables dd, pp and oo are all two digit hexadecimal values (00 to FF). These timing parameters are
immediately stored in E2PROM, and take effect right away.
Radiometrix Ltd, M48A-869-FPX3 modem manual
page 6
RADIOMETRIX [ RADIOMETRIX LTD ]
