Add RoomAlert 12S

SNMP Walk does not include everything in MIBs file (assuming because not all addon devices are connected). Device does not show network activity like other RA devices do (3E for example)

https://p.libren.ms/view/0ae68ef5
https://p.libren.ms/view/288bcc0c
https://p.libren.ms/view/6f22785c

MIB Contents here: ----defines ROOMALERT12S-MIB for SNMP agent extension of Room Alert 12S--Con - Pastebin.com