29515 is the TG (Talk Group) for Avon Police Dispatch, on the MARCS-IP P25 system. For the MARCS P25 system you program CC's (Control Channel frequencies) and AC's (Alternate Control frequencies). Trunk systems assign a frequency every time a radio is keyed up. So no one on a trunk system has an assigned frequency. Agency's (police, fire and so on) are assigned to Talk Groups. Talk Groups can be loosely defined as Virtual Frequencies.
774.78125 is the CC (Control Channel). 773.83125, 774.28125 and 774.53125 are the AC (Alternate Control channels) for the MARCS Cuyahoga County Simulcast System. I monitor Avon Lake PD on the Cuyahoga County MARCS Simulcast System Site.
There are two Lorain sites that may or may not carry the Avon PD traffic.
770.20625 CC and 770.60625 AC for the Elyria MARCS Site.
770.90625 CC and 773.08125 AC for the Grafton C.I. MARCS Site.