(Motorola Data Communications), also known as Stat-Alert
, is a Motorola two-way radio low-speed
data system using audio frequency shift keying, (AFSK). MDC-600 uses a 600 baud
data rate. MDC-1200 uses a 1,200 baud data rate. Systems employ either one of the two baud rates. Mark and space tones are 1,200 Hz
and 1,800 Hz. The data are sent in bursts over the radio system's voice channel.
MDC signaling includes a number of features: unit ID, status buttons, emergency button, selective inhibit, radio check, and selective calling
. These features are programmable and could be used in any combination desired by the user. They are typically incorporated in high-end analog FM
commercial and public safety radios made by Motorola and other manufacturers. In addition to Motorola, at least two other companies make compatible base station decoders
Motorola radios with MDC options have an option allowing the radio to filter
out data bursts from the receive audio. Instead of hearing the AFSK
data, the user hears a short chirp from the radio speaker each time a data burst occurs. (The user must turn on this feature in the radio's option programming settings).
A general option setting for all MDC systems is to enable or disable an acknowledgement
(ack) data packet. For example, following a selective call, the called radio replies with an ack
. This data "handshake" confirms the called radio is powered on, has received and decoded the call. The... Read More