The TOBY-L2 allowed to skup the user/pass string fields when no
authentication was requested, but according to the AT command
reference, all the remaining u-blox modules do require these two
fields given always (e.g. just as empty strings).
As per this sequence in a TOBY-L4:
(ttyACM2): --> 'AT+UAUTHREQ=?<CR>'
(ttyACM2): <-- '<CR><LF>+UAUTHREQ: (1-4),(0-2),,<CR><LF><CR><LF>OK<CR><LF>'
(ttyACM2): --> 'AT+UAUTHREQ=1,0<CR>'
(ttyACM2): <-- '<CR><LF>+CME ERROR: 4<CR><LF>'
It should have been: AT+UAUTHREQ=1,0,"",""
Aleksander Morgado
d134402efc