Radios with two-tone sequential decoders may monitor all system traffic or remain muted until called, depending on the system design. When the radio receives the correct tones in the proper sequence, it may momentarily buzz or sound a Sonalert. An indicator light may turn on and remain latched on. In most systems, the radio's receive audio would latch on if normally muted. In systems using a combination of audible tone sequences and CTCSS, it is common practice to turn off the CTCSS encode while the two-tone sequence is sent. This means system users with CTCSS decoders do not have to listen to the paging tones.