Editing DECT (section)

=== Physical layer ===
The DECT [[physical layer]] uses FDMA/TDMA access with TDD.

[[Gaussian frequency-shift keying]] (GFSK) modulation is used: the binary one is coded with a frequency increase by 288&nbsp;kHz, and the binary zero with frequency decrease of 288&nbsp;kHz. With high quality connections, 2-, 4- or 8-level differential PSK modulation (DBPSK, DQPSK or D8PSK), which is similar to QAM-2, QAM-4 and QAM-8, can be used to transmit 1, 2, or 3 bits per each symbol. QAM-16 and QAM-64 modulations with 4 and 6 bits per symbol can be used for user data (B-field) only, with resulting transmission speeds of up to 5,068{{nbsp}}Mbit/s.

DECT provides dynamic channel selection and assignment; the choice of transmission frequency and time slot is always made by the mobile terminal. In case of interference in the selected frequency channel, the mobile terminal (possibly from suggestion by the base station) can initiate either intracell handover, selecting another channel/transmitter on the same base, or intercell handover, selecting a different base station altogether. For this purpose, DECT devices scan all idle channels at regular 30{{nbsp}}s intervals to generate a received signal strength indication (RSSI) list. When a new channel is required, the mobile terminal (PP) or base station (FP) selects a channel with the minimum interference from the RSSI list.

The maximum allowed power for portable equipment as well as base stations is 250&nbsp;mW. A portable device radiates an average of about 10&nbsp;mW during a call as it is only using one of 24 time slots to transmit. In Europe, the power limit was expressed as [[effective radiated power]] (ERP), rather than the more commonly used [[equivalent isotropically radiated power]] (EIRP), permitting the use of high-gain directional antennas to produce much higher EIRP and hence long ranges.