I have finally figured out some options on my Telex Basic M42 ASR (thanks to greenkeyer Leanne for a copy of 516M). 
But when I get to the end of the User Programmable Options list, I am stuck. 
How do I access the Installer Programmable Options like baud rate, answer-back, etc. 

Probably the magic switch is staring me in the face, but I can’t figure it out. I am fully prepared to slap my forehead and say Doh! if someone can please enlighten me. 
Cheers
Nick

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Nick England K4NYW
www.navy-radio.com