There was a limitation in the past in the plugin, because one of the steps
during the dial (CONNECT_3GPP_CONTEXT_STEP_PDP_CTX) was to reconfigure a
specific CID hardcoding the IP type to IPv4.
That logic was removed in commit af2d6c1c4b,
but we didn't remove the IPv4 limitation at that point.
some ITM family modems require full parameters:
AT^SGAUTH=cid,type,user,pwd
even when type is AUTH_NONE.
Fortunately, all modules of the IMT family tolerate this syntax,
so it can be adopted for the entire family.
the AT^SCFG="Radio/Band" command does not return a different answer
for different charsets.
This code was working previously because the charset was left to default (GSM)
at the time of this operation, and therefore the string was unchanged anyway.
CHAP is almost universal nowadays, and so it is a better default
than PAP
Not changed for uBlox, that prefers an error if not specified,
and for Huawei, which uses NONE with user/pwd and has 2 CHAP choices
Charset definition moved from enable state machine to init state machine,
so that the right current charset is available also during further
initialization steps
Not all Cinterion modems support AT+CESQ.
However a much larger group of them support AT^SMONI
This commit uses the latter instead of the default former.