Why my xtend-pkg-R runing at 9600 is not as good as 115200?

Hi! I am new here, I have problem on using the 9600(BR=0) link rate between base and remote, the bad packet is a lot higher in BR=0 than the case of 115200(BR=1). I thought BR0 is supposed more reliable than BR1. The Configurations are:

The base Antenna on the roof, remote antenna is indoor(under the roof, on the road results are the same).

The Base settings are: (use default value for other registers)
AP0 ;No API.
BD7 ; Interface baud rate 115200
BR0 ; 9600 Link Rate
PL4 ; 1 Watt
DTffff ; broadcast
PB3 ; poll begin address
PE3 ; poll end address

The remote settings are: (use default value for other registers)

AP0 ;No API.
BD7 ; Interface baud rate BD7 115200
BR0 ; 9600 Link Rate
PL4 ; 1 Watt
DT000 ; Remote
MY3 ; my source adddress, ID3

The remote is connected LOOP Back connector.
I used the X-CTU range test with 200 bytes packet.

In BR=1(115200) case : no bad packet at all.
in BR=0(9600) case: No good packet unless Data receive time out set to 2000 ms, then about 80% correct. (All other settings are the identical)

Are there registers I didn’t set correctly?

Thank you for your help.


Your problem is a matter of flow control. Your interface data rate is much faster than the RF data rate. The radio simply can’t get the message out (and a response back from the loopback) fast enough before the X-CTU sends another piece of data and has timed out of the first operation.

If you use a data rate on the serial side that is faster than the data rate on the RF side, you should either send data much slower (which the X-CTU range test isn’t set up to do by default) or use flow control (set this in the PC Settings tab of the X-CTU).

More information is found on p. 13 of the product manual:

Thank you very much, you have solved my problem.
However, the manual said, there is 2.1kb buffer for DI, and the Range test send 200 characters per 3 or 4 seconds. The interface baud rate should not be a problem, since the DI buffer won’t get overflowed. I guess I need read manual more detail.


You are correct about the buffer in the XTend. The messages are being buffered correctly by the radio, but the X-CTU doesn’t understand that and simply times out because it didn’t see the return of its packet in time, and send s another one, which in turn does the same thing. Using flow control will help X-CTU with the range test. If you were to transfer a file of 2.1kB or less, you would see it work correctly without issue or flow control needed, but the X-CTU simply isn’t set up for this type of communication.


Thanks. Good to know!