Abstract: A statistical switching method is described. The method involving computing tags from a packet to identify the flow a packet belongs to, looking up the tag in a table to provide switching information and using the switching information to switch the packet without analyzing the whole packet. If there is no entry for the flow based on the tag generated from the packet, the packet is sent to a router for further analysis. When the analysis is complete the switching information is provided to the table. If a packet which computes the same tag arrives at the switch before the router has finished analyzing the first packet of the flow, the new packet is dropped. The statistical switch has a non-zero probability of misdirecting a packet due to the possibility that two packets belonging to different flows may produce the same tag. The statistical switch provides high-speed switching and routing capabilities at low cost.

Abstract: An atomic type switch mesh is combined with standard local area network links, such as high speed Ethernet, and a bridge-like protocol to provide a high performance scalable network switch. The network switch comprises a plurality of switch nodes, a first set of communication links which are coupled between switch nodes internal to the network switch, and a second set of communication links which comprise network links from switch nodes on the border of the network switch to systems external to the network switch. The respective switch nodes include a set of ports (having more than two members) which are connected to respective communication links in either the first or second set of communication links. Each port in the set comprises a medium access control (MAC) logic unit for a connectionless network protocol, preferably high speed Ethernet.

Abstract: The present invention provides a method and an apparatus for connecting a plurality of subscriber loops to a pool of modem resources in a way that limits the amount of modem resources that are required. The present invention uses statistical multiplexing, such as is used in Ethernet (instead of a fixed time slot TDM as is used in a telephone system) to connect the plurality of subscriber loops to the modem resources. In order to implement the statistical multiplexing, communications between a plurality of remote modems coupled to a plurality of subscriber loops and modem resources within a central site modem must be flow controlled at the carrier layer, as is done in an Ethernet.

Abstract: The present invention allows telephone subscriber loops carrying data traffic between computer systems to be switched to an alternative connection through a data network, thereby unloading data traffic from the telephone network. The invention operates by means of a break switch, which selectively switches a plurality of subscriber loops between a central office switching system and a data network. The break switch is coupled to a concentrator which takes a plurality of inputs from the break switch and connects them to a smaller number of modems in a modem pool. The concentrator allows a subscriber line to connect to different types of modems within the modem pool, depending upon requirements of a particular subscriber line user. The modem pool connects through a network interface to a packet-switched network, such as the Internet. A number of different methods can be used to transmit a command to switch a subscriber loop from the central office switching system to the packet-switched network.

Abstract: The present invention allows telephone subscriber loops carrying data traffic between computer systems to be switched to an alternative connection through a data network, thereby unloading data traffic from the telephone network. The invention operates by means of a break switch, which selectively switches a plurality of subscriber loops between a central office switching system and a data network. The break switch is coupled to a concentrator which takes a plurality of inputs from the break switch and connects them to a smaller number of modems in a modem pool. The concentrator allows a subscriber line to connect to different types of modems within the modem pool, depending upon requirements of a particular subscriber line user. The modem pool connects through a network interface to a packet-switched network, such as the Internet. A number of different methods can be used to transmit a command to switch a subscriber loop from the central office switching system to the packet-switched network.

Abstract: The present invention allows a modem to operate in both the voice band, from 300 to 3400 Hz, and also in the ADSL band, which extends above 3400 Hz. Unlike conventional ADSL modems, the present invention avoids the computationally-intensive operations required to extract all the available band of a telephone subscriber loop. Consequently, the present invention can be implemented with low-cost modifications to existing voice band modems. The present invention thereby offers higher data transfer rates at a fraction of the cost of more complicated ADSL modems. The present invention also provides bypassing functions, which allow communications through a modem located at the telephone central office side of a subscriber loop to be switched through a packet-switched network, which is capable of accommodating high data transfer rates, instead of a central office switching system, which generally imposes unnecessary limitations on data transfer rates.

Abstract: The present invention allows a modem to operate in both the voice band, from 300 to 3400 Hz, and also in the ADSL band, which extends above 3400 Hz. Unlike conventional ADSL modems, the present invention avoids the computationally-intensive operations required to extract all the available band of a telephone subscriber loop. Consequently, the present invention can be implemented with low-cost modifications to existing voice band modems. The present invention thereby offers higher data transfer rates at a fraction of the cost of more complicated ADSL modems. The present invention also provides bypassing functions, which allow communications through a modem located at the telephone central office side of a subscriber loop to be switched through a packet-switched network, which is capable of accommodating high data transfer rates, instead of a central office switching system, which generally imposes unnecessary limitations on data transfer rates.

Abstract: The present invention allows a modem to operate in both the voice band, from 300 to 3400 Hz, and also in the ADSL band, which extends above 3400 Hz. Unlike conventional ADSL modems, the present invention avoids the computationally-intensive operations required to extract all the available band of a telephone subscriber loop. Consequently, the present invention can be implemented with low-cost modifications to existing voice band modems. The present invention thereby offers higher data transfer rates at a fraction of the cost of more complicated ADSL modems. The present invention also provides bypassing functions, which allow communications through a modem located at the telephone central office side of a subscriber loop to be switched through a packet-switched network, which is capable of accommodating high data transfer rates, instead of a central office switching system, which generally imposes unnecessary limitations on data transfer rates.

Abstract: The present invention allows a modem to operate in both the voice band, from 300 to 3400 Hz, and also in the ADSL band, which extends above 3400 Hz. Unlike conventional ADSL modems, the present invention avoids the computationally-intensive operations required to extract all the available band of a telephone subscriber loop. Consequently, the present invention can be implemented with low-cost modifications to existing voice band modems. The present invention thereby offers higher data transfer rates at a fraction of the cost of more complicated ADSL modems. The present invention also provides bypassing functions, which allow communications through a modem located at the telephone central office side of a subscriber loop to be switched through a packet-switched network, which is capable of accommodating high data transfer rates, instead of a central office switching system, which generally imposes unnecessary limitations on data transfer rates.

Abstract: A flow based network switch function is based on a route cache and flow detect logic which generates hash codes for use in accessing the route cache. Flow detect logic is implemented with read-write register functions. A network switch which comprises a port for access to a communication medium to receive incoming frames. A route table memory has a set of accessible locations for storing routing information. The set of accessible locations is addressable in response to N bits, and locations in the set store a tag comprising M bits for identifying a network flow. Routing information is also stored in each of the accessible locations for the identified network flow. Flow detect logic is coupled with a port and monitors frames received by the port generate and N bit address, and an identifying tag comprising M bits for use in accessing the route table memory in response to an incoming frame on the port.

Abstract: An atomic type switch mesh is combined with standard local area network links, such as high speed Ethernet, and a bridge-like protocol to provide a high performance scalable network switch. The network switch comprises a plurality of switch nodes, a first set of communication links which are coupled between switch nodes internal to the network switch, and a second set of communication links which comprise network links from switch nodes on the border of the network switch to systems external to the network switch. The respective switch nodes include a set of ports (having more than two members) which are connected to respective communication links in either the first or second set of communication links. Each port in the set comprises a medium access control (MAC) logic unit for a connectionless network protocol, preferably high speed Ethernet.

Abstract: An apparatus for emulating a floppy disk drive using flash EPROMs. The apparatus transfers data between a floppy disk controller and a flash EPROM memory module, wherein the floppy disk controller operates under a first protocol and transmits requests to write data to a floppy disk in response to address marks. The flash EPROM operates under a second protocol. The invention includes control means compensating for the difference in the two protocols. In addition, the control means provides for the situation when power is terminated during the write process. Furthermore, the invention includes a means for organizing and reorganizing data in the flash EPROM to make most effective and efficient use of the flash EPROM memory module.

Abstract: A single-tone receiver for a device which only needs simple data which can be encoded in the seven or eight single tones which can be generated by an ordinary pushbutton telephone is provided. A telephone line interface circuit receives a signal from the telephone line. The input signal is not filtered to separate the high-frequency tones from the low-frequency tones prior to their detection. A zero crossing detector coupled to the telephone line interface detects zero crossings of a received single-tone input signal. A microprocessor coupled to the zero crossing detector counts the number of zero crossings in a period and compares the count to counts corresponding to each of the seven single-tone frequencies.

Abstract: Apparatus and method for providing tone operating capability to a dial telephone is disclosed. The standard mouthpiece together with the original microphone of the dial telephone are removed. The present invention provides a replacement mouthpiece attached to the telephone in place of the standard mouthpiece. The replacement mouthpiece includes a relatively small microphone electrically coupled to the transmitter connections in the telephone and having a sound receiving element. A plurality of keyboard elements are located in the replacement mouthpiece generally around the sound receiving element of the microphone. The keyboard elements correspond to respective telephone operating digits and symbols and are adapted to be actuated by the user of the telephone.The replacement mouthpiece includes means for generating an output signal responsive to the actuated keyboard elements to operate the telephone.