It is very random that I found this thread.
Trimble can get corrections via NTRIP and via RS232 with Teltonika RUT955 router. We have developed this feature so that RUT955 can be used as a link (Over LTE) between navigation device (Trimble, etc) and RTK base station.
However I am not sure if it would work with your setup as I understand only half of what you guys are talking here about.
Greetings from Teltonika HQ in Lithuania.