Adjacent Channel Selectivity (ACS) is a receiver performance metric that specifies how well it can tune into its assigned frequency while ignoring powerful transmissions in neighboring bands. It depends heavily on the quality of the receiver's filtering and dynamic range. If a receiver has poor ACS, a strong adjacent signal will overwhelm its front end, causing desensitization and dropping the connection.
The base station has excellent ACS, so it won't be deafened by the high-power paging transmitter next door.
Related terms
ACRR
A receiver's ability to isolate a desired signal from a strong interfering signal on a neighboring frequency.
ACIR
A metric defining the ratio of total transmitted power to the interference power affecting a neighboring channel.
ACI
A type of signal degradation caused by energy spilling over from a neighboring frequency band.