Specifications are subject to change without notice or obligation.
Time-Division Multiple Access
Uses the full 12.5 kHz channel and divides it into two independent time slots to
achieve 6.25 kHz efficiency. This doubles the calling capacity in one frequency
channel for two simultaneous digital conversations to occur in a single channel. Or,
use one time slot for voice and the other for data such as text messaging. Achieve
double capacity without relicensing or rebanding and avoid degradation in range
performance or interference with adjacent channels.
2 For 1: Get Two Digital Voice Paths From One 12.5 Khz Channel.
Additional benefits of TDMA:
• Backwards compatible with legacy analog systems for easy, efficient conversion to digital.
• Reduced equipment cost – no extra repeaters or combining equipment required to get double the capacity.
• Longer battery life and greater power efficiency – TDMA reduces transmit time in half for improved battery performance, increasing
talk time length on a single charge. Less infrastructure equipment is required, which leads to less energy needed to operate.
• More choices – TDMA is the most widely used digital mobile radio protocol in the world. Using TDMA digital radios gives users a
more flexible radio system.
Frequency-Division Multiple Access
Splits a frequency band into narrow subchannels and does not use the full capacity of
the entire 12.5 kHz channel. As a band narrows, there is greater risk of interference,
reduced sensitivity and potentially reduced range, resulting in overall reduced
performance quality. Relicensing or rebanding is necessary, adding more cost to
Only One Digital Voice Path Is Achieved In One 12.5 Khz Channel Without
Other limitations of FDMA:
• Increased equipment cost – a dedicated repeater is required for each channel. Combining equipment is also required for multiple
frequencies to share a single base station antenna.
• Increased licensing cost – relicensing or re-banding is necessary to achieve increased capacity. Cannot fully operate two 6.25
kHz subchannels within 12.5 kHz channel. Once channel is relicensed or rebanded to get double the capacity on FDMA, the
digital system can no longer communicate with a legacy analog system as it will be on a different frequency.
• Limited choices – Not a widely used protocol and very few brands available.
Know The Difference
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Do Digital Right!
Not All Digital Radios Are the Same
Unlike analog radios where any brand of radio can work together, digital radios are manufactured based on one of two protocols:
TDMA or FDMA. It is important to note that these two protocols are not compatible; this means FDMA radios will not work with TDMA
radios when operating in digital mode. Over 74% of the digital radios deployed worldwide use the TDMA protocol for enhanced
efficiency and power.