The RCMP have been using that term around here for decades, and as far as I know it means the telephone line into the back area of the police office, a line or number that is not used by the public.
Sorry I dont have anything to say re the 107 though unless you also have a digital scanner or you have a special listening interest I bet you won't be happy with an analog scanner.
Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9780; en-US) AppleWebKit/534.8+ (KHTML, like Gecko) Version/6.0.0.600 Mobile Safari/534.8+)
I am going to go out on a limb and say that anywhere the RCMP provide community policing they will use that term. It is refering to an unpublished phone number to the detachment that is not forwarded to their OCC during after business hours. Officers usually will simply say 'call the back line.' In all my years of listening to RCMP I have never heard an officer give a detachment back line number OTA.
Same here. It just means the non-published line into the detachment. The published line is generally answered locally during the detachment's open hours, and forwarded to the OCC (dispatch center) at all other times.