Need Help!- Bridgeport Series 1 Boss 5 PC file loading

[Electricky]

I have a friend with a Series 1 with Boss 5. He needs to be able to transfer programs from a PC.
The machine has been "played with" by someone who said he knew what he was doing. He apparently could not communicate. The machine has a BTR3-0 board which he removed and replaced with one of his own. I have the original board and can refit. From what I have gleaned this is a "Behind Tape Reader" board which allows access via RS232 from a PC. The board has an 8 way dip switche (SM1) but I have no info as to settings. The board Eprom is marked as "BTR3B 11/4/60"

Can anyone offer any information?
Once I can chat to the system is there a preferred piece of software for transferring programs?

Thanks for any help

[machintek]

Rs232 was achieved with the local port going to the ERS board. It was also capable of 20ma current loop to a teletype depending on pins used.
The large connector on the ERS must be pulled and left hanging for RS232. Baud rate is set by DIP switches on the ERS.
The tape reader used a parallel interface. The BTR is used in place of the DNC loader for large programs exceeding the machine memory.
There is a LOT of data on this forum about all of this. Just search for it.

George