Cannot change SH and SL problem

I have ZNET 2.5 modules. Firmware version 1241(1041) AT. Hardware version 1941. Problem is:

I have 50 devices with ZNET modules. These devices should be in some area. ZNET modules in devices are just there for wireless RS-232. Every ZNET module in devices is set to communicate with one (51st device with node identifier NI=READER01) ZNET module. That module is used to readout devices. Before mounting every ZNET module in devices was set:
Now ZNET modules in devices have DH and DL identical to SH and SL of the READER01.

Everything works fine.

But, if I don’t have original READER01 module (broken, missing etc.), I cannot communicate with devices, because other module has other SH and SL even if it has the same NI=READER01.
It is not possible to change SH and SL of the module.


  1. Is there any solution to my problem?

Thanks for reading this inconclusive thoughts

Hello Milan,

You are correct, there is no way to modify the SH and SL of a radio.

I see two methods:

If you have intelligence on your 50 devices, you could resolve the name of READER01 by using the DN command on each of your devices to set DH and DL. If you replace READER01, all you have to do is maintain the name of the new node to be READER01 and your network will continue to operate.

If intelligence is not available on your devices then I would recommend changing your 51st device (READER01) to run the API-mode firmware. You could then apply the following method to modify the DH and DL of all of the nodes on your network:

  1. Either keep a list of all devices on your network in your program or execute a node discovery to find all devices on your network.

  2. For each device send a Remote AT Command Request (API Identifier 0x17) setting DH and DL and then write these values to flash with WR.

That’s all!

Please let us know if you need further assistance.

Good luck!

Thank You very much. It would be helpful if I understood correctly, I don’t have to change anything in modules that are already installed on devices (AT firmware)? I only have to change firmware on READER01?
Cordially, Milan.