I am experiencing dropped calls from my NEC DT800 phone, which is connected directly by ethernet cable to a LAN port on my G3100 router.
I believe that SIP ALG can not be turned off in this router. Is this still correct ?
Has anyone found a solution to this problem. Is there a work-around ?
That's correct. SIP ALG was never made into the specifications of either G1100 or G3100.
However, a new router on the horizon, namely the CR1000A, may have SIP ALG option given it comes from a 5G router vendor, and routers on the 5G side contain this feature for many years.
You may need to wait a few months before the new router is generally available.