What is the difference between RDS and RCC?

RCC (Radio Controlled Clock) is a time system built based on the shortwave transmissions. Shortwave signals can be received far from the signal station since its coverage area is wide. Yet, the transmitting stations are still far from Hong Kong to a great extent; signal is hence very weak, which results in the RCC clocks incapability of synchronizing.

RDS, on the other hand, is built upon the FM broadcasting system. Although FM broadcasting system’s coverage scope is not as wide as RCC’s, Hong Kong is well covered by seven local transmitting stations, as a result broadcasting in Hong Kong is highly accessible. Accordingly, wherever there is broadcasting, RDS clocks can synchronize.