Abstract: A dual port external wireless modem is disclosed. According to one embodiment, the external wireless modem receives command and control information over a primary serial port, and real-time data over a secondary serial port. The primary serial port is further configured to received packet switched data, such as short message service messages, while the secondary serial port is configured to received circuit switched data. An RF transceiver in the wireless modem modulates data and control received over the respective serial ports, preferably using a GSM protocol stack. According to an embodiment, the circuit switched and packet switched data received at the wireless modem can be simultaneously transmitted by the RF transceiver without interrupting the circuit switched data transfer, thereby avoiding a context switch and a loss of throughput.

Abstract: A GPRS controller interface communicates commands, events and data between two communication devices using a GPRS transport layer (GTL). In one embodiment, communication devices may include a host and a baseband controller of a modem that communicate over a serial link. Command event and data packets may be framed and multiplexed for transmission over the link. The framing includes, among other things, adding a flag to identify command and event packets from data packets, and a sequence number to help ensure synchronization. A first logical channel may be utilized for command packets including AT modem commands. A second logical channel may be utilized for outbound data packets. A third logical channel may be utilized for event packets, and a fourth logical channel may be utilized for inbound data packets. GTL commands may initiate an initialization or resynchronization of the GCI layer and may be generated, for example, in response to sequence number errors of check-byte errors.

Abstract: A data collection system for transmitting data from user equipment to a user application server over a GSM network is provided. According to an aspect of the invention, a data terminal apparatus is configured to simulate a circuit switched call link to the user equipment, while providing a communications call link to the GSM network over a non-circuit switched call link. According to embodiments described herein, the non-circuit switched call link is achieved via packetizing serial data from the user equipment into short message service messages, or alternatively via general packet radio service messages. As a result of the methods and apparatuses of the present inventions, legacy serial communications equipment can be integrated into a data collection network and remotely monitored without the costs associated with deploying service personnel or more costly circuit switched type equipment and services.

Abstract: A data terminal apparatus comprising a wireless radio and a communications bridge is provided. The data terminal apparatus provides a link between data from a user equipment and a GSM network, connecting user equipment designed for circuit switched call link communications to a destination equipment via short message service or general packet radio service communications. According to an aspect of the invention, the data terminal apparatus simulates a circuit switched call link to the user equipment, thereby bridging legacy serial data communications systems with convenient wireless network technology. The result is a highly portable and easily integrated data terminal appartus for a wide variety of user equipment. In one embodiment, the invention is particularly advantageous in utility service monitoring applications.

Abstract: A GPRS controller interface communicates commands, events and data between two communication devices using a GPRS transport layer (GTL). In one embodiment, communication devices may include a host and a baseband controller of a modem that communicate over a serial link. Command event and data packets may be framed and multiplexed for transmission over the link. The framing includes, among other things, adding a flag to identify command and event packets from data packets, and a sequence number to help ensure synchronization. A first logical channel may be utilized for command packets including AT modem commands. A second logical channel may be utilized for outbound data packets. A third logical channel may be utilized for event packets, and a fourth logical channel may be utilized for inbound data packets. GTL commands may initiate an initialization or resynchronization of the GCI layer and may be generated, for example, in response to sequence number errors of check-byte errors.

Abstract: A communications bridge for simulating circuit switched call links to user equipment is provided. According to one embodiment, the communications bridge receives data from the user equipment over a serial data interface. The communications bridge simulates circuit switched call link responses back to the user equipment so that the user equipment believes that a circuit switched call link has been made. Once the simulated circuit switched call link is established, data from the user equipment is packetized into short message service or general packet radio service packets for transmission over a non-circuit switched call link.