User's Manual

6-10
Byte position Function Possible values
1 RF Terminal ID 0-F
2+ Illegal Command ?
Last Termination of message CR (ASCII 13)
For example, if Terminal #2 received an illegal command, the Base station
would transmit to the host:
2?CR
• If a command is sent from the host to the base station without a valid
terminal ID character, such as:
@1,1,1,Scan Serial Number
since the command doesn’t specify which terminal it is meant for, the base
sends the following message back to the host:
*
?CR
Base Station Initialized Message
Whenever the Base Station is powered up, it sends a message back to the host as
follows:
Byte position Function Possible values
1 BASE ID * (Base ID is fixed)
2+ Base Initialization DC3 (ASCII 19)
Last Termination of message CR (ASCII 13)
Since ASCII 19 is XOFF, the ASCII 19 character can be changed to ASCII 20
for XON/XOFF sensitive systems by changing the Base Station Setup. See
Chapter 2; RF System Setup for details.
The Base Station Initialized message is provided so that the host will know that
there has been a power interruption on the Base Station. When a serial device
powers up, the first byte transmitted is often garbage. QBASIC handles the
garbage character without incidence, but GWBASIC does not unless ON
ERROR GOTO is used to trap the error. Be aware of this potential garbage-byte
problem in your programming. To isolate and test for the problem, power up the
Base without the serial cable connected. After you power the Base up, plug in
the serial cable. You will not see the “Base Initialized” message but it should
not matter when testing for the garbage data.
If a terminal is signed-on to the system, and the base station is re-initialized, the
following message is sent to the terminal:
Base Reinitialized X
Cycle Power on RF
Terminal and Sign-on
again to Restart_