Abstract: The invention provides an impedance adapter that automaticaly switches to impedances that match network transmit/receive lines impedances (105,106) by a controlled switching of various impedances mounted serially/parallely with connected transmitter/receiver (100,101). For a high speed adapter, a balanced transmitter/receiver is required for limiting crosstalk effect due to the high transmission rate. Transmit/Receive impedance adaptation networks (102-103) are composed of serial/parallel networks of resistors and relay contacts that are switched independently by magnetic coils of an impedance switching circuit (110) and having values conformable to the various network impedances imposed by different national regulations. By using the principle of double deviation voltage technique, a measuring circuit (108) detects upward and downward voltages (VA,VB), VB amplified by 2 to generate an analog signal VS (VS=VA-2VB) to a control logic circuit (109).

Abstract: The invention relates to a method and a system for routing messages or frames through network nodes connected to each other by network links and connected to a plurality of terminals by different input/output ports also called network attachment cards (NAC) in a multi-node communication network. In such a configuration, each terminal equipment stores a network table. The network table is updated in the terminal itself by a network manager which may by the way limit the access of the terminal to some terminals of the network. To route an incoming message or frame from a source terminal (T1) to the destination terminal (T7), a routing algorithm is implemented in each NAC. Each NAC has a different and unique integer address in the node, each node has a different and unique prime number address greater than the number of NACs in the node. Each terminal connected to a node sends frames with a routing identifier (RI). The different RIs are located in the network table.

Abstract: In a token ring network a periodic recirculating frame having a plurality of information carrying slots and a header section is used for enabling a plurality of telephone stations to exchange information carrying signals. The header is provided with a token which can assume one of three states. In the first state FF, a telephone station wanting to make a call, changes the token to the second state 00 and inserts call establishment information in the header. A server station also connected in the ring detects the second state as a request to establish a connection from and to a station specified in the header. The server changes the token to the third state AA and inserts a slot assignment in the header. All stations receiving a frame with a token in the third state examine the header. The calling station implies confirmation of the requested connection and the called station is made aware of the call and the identity of the caller.

Abstract: A token ring interconnects a plurality of telephone stations and a ring server station. All communication is conducted via a TDM frame which includes a START field, a TOKEN field which can have any one of three states (free, busy or dedicated to communication by the ring server station), calling and called station address fields, a field for data to be sent to the ring server station and a plurality of data slots via which the telephone stations exchange data once the slots are allocated. When a connection is desired by a station it seizes a free token by making it busy, inserts pertinent field data and send the TDM frame on to the ring server station which establishes the connection via an answer frame.

Abstract: A method for initializing ISDN adapter cards installed within a workstation having a main processor and an ISDN primary adapter for connecting the ISDN adapter cards to an ISDN primary gateway. Each ISDN adapter card has circuits for handling at least one B-channel, and a first processor associated with memory storage. The ISDN primary adapter includes a second processor associated with a second memory storage. In response to the reception of a specific polling pattern transmitted to each adapter card by the primary adapter, a pattern is transmitted to the workstation processor for requesting the loading of the second memory storage with operational code transferred from the workstation to the ISDN adapter card.

Abstract: Method for transmitting a unique high-rate digital data flow over n multiple different independent digital communication channels between two different primary terminal adapters. The method involves the steps of establishing, on request of a first DTE to a second remote DTE, a set of n independent digital communication channels between said terminal adapters and determining, during an initialization phase, the relationship between the slot of each channel used for the building of an aggregation superchannel and the chronologic order of the establishment of the considered slot. Then, the high-rate digital data flow is separated into bytes and each byte is transmitted through the independent digital channels in accordance with the chronologic order which was previously assigned to each of the said channels.

Abstract: An apparatus for connecting a data communication equipment, such as a data terminating equipment (DTE) to an ISDN digital communication network providing a first 64 kbps and a second 64 kbps B digital communication channel which involve different transmission delays. The apparatus includes a transmit part with a separation for separating a unique high rate 128 kbps data flow into two distinctive 64 kbps data flows to be transmitted through both B channels. The apparatus includes a receive part (9999) including storage for storing the data received from digital network, measurement and comparison circuits for measuring the difference between the two transmission delays, address generators for addressing the storage in order to extract the data received through both digital channels, control circuits responsive to the measure and comparison for controlling the address generators in order to provide a 128 kbps which is not affected by the difference of transmission delays introduced by both digital channels.

Abstract: A store and forward apparatus includes a deserializer for deserializing received frames of data into a sequence of n-bit words. Each frame includes a header, a data field and a frame checking sequence (FCS) generated by a first telecommunication node. The apparatus includes a storage for storing the deserialized n-bit words, and a processor for addressing the storage and for generating n-bit words corresponding to a new header of the received frame. The apparatus also includes a serializer receiving the n-bit words from the storage for generating a new frame having a new header field and a new FCS to be transmitted to a second telecommunication node. The apparatus further includes a receiver for receiving a frame and computes a first partial FCS covering the frame's data field only and a storage for storing the first partial FCS. During forwarding, n-bit words to be transmitted are simultaneously received by the serializer and by an apparatus for computing a second partial FCS covering the data field only.

Abstract: A terminal adapter for a telecommunication network having a receiver for multiple HDLC communication channels. The receiver includes a BCC calculator for computing and checking the validity of a received HDLC CNM frame. The terminal adapter further includes a device for detecting the reception of a specific CNM header included in a CNM frame on any of the HDLC communication channels and responsive to the detection for setting the BCC calculator to a predefined state. The latter state corresponds to the state of the BCC calculator after a computation of BCC for the specific CNM header. Therefore the BCC calculator can proceed with computation of said BCC for the CNM frame.

Abstract: A rate adaptation system for adapting the rate of a communication stream between a first communication device (TE) and a second communication device (NT). The first communication device transmits and receives data at a first given rate and the second communication device transmits and receives data at a second rate higher than said first rate (generally 8, 16, 32 or 64 kbits/s). The rate adaptation system includes a transmit part (620) which allows the transmission from the first communication device to the second communication device by means of a bit repetition and framing function. The rate adaptation system also includes a receive part (630) which allows the transmission from the second communication device to the first communication device.