phones, which are regulated by Part 15 of the FCC's regulations, have made amateur use of the upper and lower end of the 33 centimeter band somewhat tricky due to the number of these phones used by the general population. Part 15 devices, by law, must accept interference from any licensed radio service with which they share frequencies. 900 MHz wireless networking In the early 1990s, wireless computer networking was just becoming affordable. Several competing technologies emerged that made use of the 902-928 MHz Part 15 band, such as: NCR/AT&T/DEC/Lucent WaveLAN. 915 MHz, 250 mW transmit power. Obsolete, but still in use in certain areas. Aironet (now Cisco) ARLAN. 902-928 MHz with 12 channels, 450 mW transmit power. Obsolete, but still in use in certain areas. Alvarion BreezeACCESS 900. 902-928 MHz, 200 mW transmit power. Still being sold and in use in certain areas as of 2008. A now defunct commercial user of 900 MHz wireless networking was Ricochet. They used 900 MHz for the "last mile" connection to the user in an early wide area mobile wireless network. Motorola Canopy is also used by WISPs depending on the Line-of-sight propagation XG Technology, Inc. xMax. 902-928 MHz. Less than 1 W. A cognitive radio system still being sold and in use as of 2011. ISM: 915 MHz Long Range WAN (LoRaWAN) Frequency range from 902 MHz to 928 MHz as an unlicensed Industrial Scientific and Medical (ISM) frequency band for North America. Started in 2009, LoRaWAN were targeting the metering industry and aimed at adding wireless communication capabilities for gas, water and electricity meters. For this purpose, they used Chirp Spread Spectrum (CSS) modulation technology, a technology widely in use for sonar in the maritime industry and radar in aviation. Walkie talkies MotoTalk or with Nextel, DirectTalk, uses the 900 MHz Part 15 band. It uses FHSS and employs 10 "channels" and 15 "privacy codes". This is available as a feature on several of the walkie-talkie phones, for "off network" simplex communications. Motorola makes a line of walkie-talkies (the DTR family) which are FHSS digital units. They are very similar to the DirectTalk-capable iDEN cellphones, even sharing some accessory items, but they can not interoperate with DirectTalk units. Trisquare makes a line of walkie-talkies (the eXtreme Radio Service family) that are also license free FHSS units, operating in the 900 MHz band. They are similar to DirectTalk but not compatible.