Abstract: In a base station of a mobile cellular telephone system of the type having time division multiple access (TDMA) channels, a radio frequency test loop is established between a predetermined downlink channel of a base station transmitter and a predetermined uplink channel of a base station receiver. The test loop is in real time, thereby eliminating the time offset of the radio channels used for communications. The radio frequency test loop includes a circuit for transposing the frequency of the carrier signal from the transmitter to a frequency that can be received by the receiver. The signal having the transposed frequency is used in tests for determining values such as bit error rate (BER), transmission signal level, or reception sensitivity.

Abstract: A cellular radio system, having a mobile services switching center (MSC) coupled to a base station by means of a pulse code modulation (PCM) link, has an apparatus comprising, in the MSC, a transcoder and rate adaptor (TRA) that generates a PCM frame from a plurality of user data blocks, each user data block corresponding to one of a plurality of users and each user data block comprising an integer number of bytes of data. In the PCM frame, each of the plurality of user data blocks occupies an integer number of consecutive bytes of the generated PCM frame, which is then output to the PCM link. The base station includes a channel encoder that generates an air interface frame from a plurality of user data blocks contained in a received PCM frame. The base station may also generate a timing control signal which is received by the MSC.

Abstract: A malfunction position detection system is disclosed for a modular telecommunication facility. Each telecommunication facility is constructed out of a plurality of modular cabinets which are positioned in a station rack. The malfunction position detection system includes switches for setting the position of each cabinet in the station rack. The cabinet position is read off of a bus connected to the switches by a plurality of electronic units connected to the cabinet. The cabinet position is stored in some of the electronic units. As a result, the cabinet position can be sent along with an error message to the cellular system when an error occurs.

Abstract: Novel tobacco compositions which--when subjected to an elevated temperature below the combustion temperature the tobacco--liberates essentially pure nicotine.