George, I may have answered the same question on another venue (post
from you?) but I believe the 5100S was a late 5100, factory wired to
accept the 51SB sideband adaptor. That's my recollection.

George wrote:
Has anyone here ever seen a B&W 5100S transmitter? I owned a 5100B with
the B&W SSB adapter back in the early 70s but never came across a 5100S.
I am thinking that it might have been a prototype of the later B&W 6100
transmitter.

Anyone have any info?


Thanks,

George - K3UD