freq is north of the 123.925 sector high level wise.
I think you mean 124.925 ? Which is the low altitude sector northeast of YYZ, primarily used by YYZ departures via YCF, MSS, etc.
I know to the west is 135.6 and 134.575 and I think an YOW tcu frequency 124.925 I believe
134.575 is a high altitude sector, directly above 124.925. North of these two sectors is 127.000 which is the low altitude sector used by arrivals into YYZ via YSO and directly above 127.000 is the high sector using 124.675.
To the east of 124.675/134.575 is the Montreal high sector (FL290 and above) on 135.600. Actually just in the last few days they have been using 134.400 in this sector instead of 135.600. Not sure if it's a permanent change or a temporary sub ? 134.400 was the previous frequency in this area that hasn't been used for a few years now.
Ottawa terminal (actually now located in Montreal) uses 135.150 (arrivals), 128.175 (departures), 127.700 (VFR Class D). Although just over the weekend they were using 127.700 for all 3, something I've never seen them do in the past. Maybe Montreal is reconfiguring some frequencies/sectors ?http://www.canairradio.com/yyz.html