@Skalman originally posted links to a Broadmobi BM818-A1 spec sheet and manual in a different thread: Librem 5 BroadMobi modem reports wrong (?) manufacturer/model info -- bug in firmware? Where to find documentation for the modem?
Specs are at: https://p.globalsources.com/IMAGES/PDT/SPEC/593/K1172549593.pdf