Hey Fredrik > I'm working with a modem that supports GSM, LTE Cat-M, and NB-IoT. Ideally, I > could both query and, more importantly, set which of these access technologies > are allowed in the modem through ModemManager's API. > > As far as I understand, ModemManager understands the concepts of (1) modes, > (2) capabilities, and (3) access technologies. From looking at the defined > enums, > (3) is more granular than (2) which is more granular than (1), but all relate > to > "access technology" in some way. (3) is the only one that differentiates > between > Cat-M and NB-IoT, but the D-Bus API only exposes "set" methods for (1) and > (2). > > The modem itself treats GSM, Cat-M, and NB-IoT at the same abstraction level: > "Selecting Radio Access Technology" from the AT command manual, so there is a > slight disconnect between MM and the modem itself wrt. access technology. > > I'm open to submitting a patch that adds the functionality I want, but I don't > know where to start attacking this problem. Perhaps MMModemCapability should > split the concept of LTE into Cat-M, Cat-1 and NB-IoT? To me, many of these > terms are ambiguous, so please note that I'm coming from a position of > relative > ignorance. >
Yes, all that is not very well managed right now in MM. We recently added some enum updates in MMModemAccessTechnology (https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/commit/664610819e45943d8619de8c090b5e58ff916c51) but not much more. Could you let us know which modem you're using and which commands (AT commands I assume) can be used to query whether Cat-M, Cat-1 and/or NB-IoT are supported, and how to change them? -- Aleksander
