Abstract: The dual mode communication network comprises a first communication system having a frame structure and a first traffic channel protocol and a second communication system having the frame structure and a second traffic channel protocol. In the network, only one of the first and second traffic channel protocols supports forward error correction coding.

Abstract: An existing cellular system (X-system 102) is interconnected with another cellular system (M-system (101) via inter-office trunks (150) to add additional switching capacity for providing telephone coverage to mobiles located throughout their common coverage area. X-system (102) includes a control terminal (120) coupled by data and voice lines to base sites (121-124) and by out trunks to a telephone central office (110). M-system (101) includes a control terminal (420) coupled by data and voice lines to base sites (411-415) and by in trunks and out trunks to the telephone central office (110). M-system base sites (411-414) are colocated with corresponding existing X-system base sites (121-124). Paging/access channels are assigned to M-system base sites (411-414) for processing all incoming originations from mobiles and paging mobiles for all outgoing originations.

Abstract: An existing cellular system (X-system 102) is interconnected with another cellular system (M-system 101) via inter-office trunks (150) to add additional switching capacity for providing telephone coverage to mobiles located throughout their common coverage area. X-system (102) includes a control terminal (102) coupled by data and voice lines to base sites (121-124) and by out trunks to a telephone central office (110). M-system (101) includes a control terminal (420) coupled by data and voice lines to base sites (411-415) and by in trunks and out trunks to the telephone central office (110). M-system base sites (411-414) are colocated with corresponding existing X-system base sites (121-124). Paging/access channels are assigned to M-system base sites (411-414) for processing all incoming originations from mobiles and paging mobiles for all outgoing originations.

Abstract: The inventive antenna coupling system is capable of simultaneously radiating an omnidirectional signal pattern for a plurality of transmitters as well as providing a directive pattern to a receiver.An antenna array is coupled to the transmitters and receiver via a plurality of antenna couplers. Each coupler includes an antenna terminal, coupled to a corresponding antenna, a transmitter input terminal and a receiver output terminal. Multiple transmitters are coupled to the transmitter input terminals through a hybrid network array. The receiver is coupled to the receiver output terminal via a logic controlled antenna switch. The antenna couplers, which may be comprised of either high pass-low pass filters or circulators provide isolation between the transmit and receiver signals.

Abstract: A modem having a transmitter portion including a first modulator connected to receive audio frequency signals and supplying an output signal through a single sideband filter to a second modulator providing an output signal at a unique channel frequency, a receiver portion including a first demodulator connected to receive transmitted signals and supplying an output signal to a second demodulator through a single sideband filter with the second demodulator providing audio frequency output signals, a carrier switch supplying a small amount of the carrier to the second modulator during operation of the transmitter and a carrier level switch associated with the carrier switch for supplying the carrier at high and low levels, and a crystal controlled channel oscillator connected to the second modulator of the transmitter portion and the first demodulator of the receiver portion with removable, plugin crystals connected thereto for controlling the channel frequency of the modem.