Before anyone speaks, you hear a brief "psssh" or click. This is the squelch opening. In Motorola radios, this is often followed by a short data burst (MDC1200 signaling).
Motorola has dominated public safety radio since the 1940s. Their systems use narrowband FM, digital (P25), or DMR modulation. zvuk toki voki motorola policija
You won’t hear a Baofeng or a Kenwood making the true police sound in most professional forces. Motorola has a near-monopoly for three reasons: Before anyone speaks, you hear a brief "psssh" or click