CSD not working on WISMO228

We are evaluating WISMO 228 module with our GSM/GPRS modem.

GPRS and SMS work fine.

However there seems to be a problem with the CSD (direct modem to modem connection).

The transmitting module would occasionally add extra symbols to the output data stream. This happens randomly.

Is this problem known? Any solution? Firmware update?

We tested a number of your modules - they all seem to have the same issue.


What is the firmware version used in WISMO, when the problem is seen.
Is CSD call not working with a particular firmware ?Did you check with other firmware versions as well?
All the tested modules have the same firmware version or you tested on different versions?


The version string is “L20_00gg.WISMO228 270410”. All modules that I have tested have the same firmware version.
I think it is too old but I can not find anything relating to the firmware. Nor the firmware downloader nor the new firmware for WISMO228.

Note that most contributors have are other customers/users - if you wish to address SiWi directly, you should contact your distributor or FAE.

A local Distributor may be able to help you with knowledge of local network conditions…

If you’re using a proper data/M2M SIM (as opposed to just a general consumer “telephony” SIM), you could try contacting the Service Provider…

Are you able to try this with any other (non-SiWi) modules?

Yes, of course. The previous version of the GSM modem on the Q24 module all works fine in the same conditions.
Yes, of course. I tried contact to the local disributor. There is no info at all. Two last months each time it says “wait two weeks for the new firmware version”. But nothing happens. No firmware downloader nor firmware.