Hello, we have a number of fax machines attached via a Grandstream ATA to a Freeswitch. Fax devices are Brother MFC. Freeswitch works in t38-passthru mode. In the last weeks we see (maybe due to software update?), that the fax devices detect, that they are siblings with extended feature sets, and then one side switches to "non standard facilities" mode by sending an NSF signal (resp NSS in wireshark). The opposite side then answers with "failed to train" (FTT). This always breaks the fax transmission. We also asked Brother to send us an advice, how to disable NSF in the fax device, but these codes did not work. The fax devices are continuing to send NSF. Besides that we have no control of the opposite fax device, who are initiating NSF. So I am asking here: How are you dealing with NSF? How did you solve this issue? -- With kind regards Peter Steinbach Telefaks Services GmbH mailto:lists (att) telefaks.de Internet: www.telefaks.de