The present document specifies the DECT derivative DECT-ISM for implementation in the 2,45 GHz ISM band [9], [10] and [11]. The main difference between DECT and DECT-ISM is the addition of frequency hopping patterns fulfilling the FCC part 15 rules [10].

The prime objective for specifying DECT-ISM is to allow for introduction of a DECT-based technology in countries that have no spectrum allocated for DECT, but allow frequency hopping applications in the ISM band. The 2,4 GHz ISM band is available in all major markets worldwide.

DECT-ISM will, compared to DECT, have limitations in range due to restrictions imposed by the ISM band rules [9], [10] and limitations in quality of service mainly due to the fact that the ISM band is unprotected, while the DECT band is exclusively allocated for DECT. See further clause 4.1. The ISM band is unprotected in that sense that it allows for uncoordinated usage of a variety of incompatible communication devices and also industrial, scientific and medical devices.

The present document defining a DECT derivative with a frequency hopping overlay, mainly aimed for the North American market, will become obsolete and will be declared historical due to new US FCC part 15 rules. Standard DECT implementations are now allowed on the US ISM frequency bands 902 MHz to 928 MHz, 2 400 MHz to 2 483,5 MHz and 5 725 MHz to 5 850 MHz.