Delighted to be able to say that the Toddington Concetrator is now working fully!
It always did work reliably to the trackside phones but we knew that we had a problem with low audio level when a signalman used it to talk from Todd to Winchcombe after much brain searching the problem was down to the design of the new modern transmission bridge. Whilst this coped with calling betwen boxes the tiny DIL relays did not have enough inductance to to ensure that the audio went out to line.
The change to a differently wound relay has done the trick and its now fully working
We will now steadily upgrade the other units that have been installed and continue with building the final one for Broadway
PS We always did have a backup system via the dial up phones throughout the system