 to send data listens to see if the frequencies are clear to send data. If it is clear then the data is sent, otherwise it waits for a random amount of time before trying to send the data again. The data within a HomeRF transmission is contained within repeating frames that are transmitted. Each one of these frames is either 10 or 20 ms long dependent upon the number of active voice calls at any given time. Within the frame, the bulk of the available capacity is used for asynchronous data transmission. However, within the capacity reserved for this, priority is given to the streaming media sessions. Up to eight of these sessions are allowed, but when fewer than this number are present, the available capacity remaining can be used for ordinary data transmission. The last part of the data frame structure is reserved for providing voice quality communications. These full duplex pairs of phone quality slots use the Digital Enhanced Cordless Telecommunications (DECT) system. The HomeRF protocols map directly onto this allowing an already well- established system to be incorporated into the HomeRF technology. The full specification for HomeRF allows for a total of eight land line quality links to be supported. Index 802.11, 282, 285-289 gain, 79 impedance, 78 location, 115 Access point, 285 log periodic, 105-107 Active antenna, 114 loop, 113 Ad hoc network, 285 materials, 116 Advanced mobile phone system, 248 parabolic reflector, 110-112 AFC, 155 phase array, 99-101 AFSK, 62 polarization, 78 AGC, 133-135 resonance, 76 AM, 53-56 safety, 118 AM broadcasting, 204-207 short, 109 AM demodulator, 152 vertical, 107-109 AM transmitter, 195 Yagi, 101-104 Ampere, 4 Apogee, 223 Amplifier, 182-188 Armstrong, Edwin, 10, 11, 13 class A, 183 ASCII, 63 class B, 183 Atmosphere, 30-33 class C, 184 Audio filter, 165 efficiency, 182 Audio frequency shift keying, 62 IF, 148 Audion, 9 RF, 144 Aurora, 43 Amplitude modulation, 53-56 Automatic frequency control, 155 modulation detector, 53 Automatic gain control, 133-135 modulation transmitter