S2C not actually backward compatible with S2B protocol

We’ve been using S2B’s for a while. Obsolete. Got S2C’s. If they are set the same (115k,n,8,1,hardware handshake, API-1) we can’t even read SH & SL from them. DOA. I have several, it doesn’t appear to be a bad chip, cause XCTU can set the baud on them just fine.

SH and SL parameter were never configurable on S2B modules either. They are just “Read Only” on both S2C and S2B.

I don’t believe you read the question correctly. We never asserted that we try to write them. Unable to query them.

Same problem is common between revE and revF of S2B: revE’s all work, revF, does not work, like the S2C doesn’t work either. They do work in the usb dongle adapter, however, so I assume the power filtering / power quality requirements changed between revE revF or something like that…

In that case contact Digi/point of purchase and get them replaced.