# US 5,347,549 A · Method and apparatus for interfacing between a twisted pair and an intelligent cell

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- Number: US 5,347,549 A
- Document ID: US5347549A
- Status: Granted
- Kind: A
- Application number: 08/049,534
- Filed: 1993-04-20
- Granted: 1994-09-13
- Earliest claimed: 1993-04-20
- Assignees: Echelon Corporation
- Inventors: Donald D. Baumann; W. Mike Berke; Stephen F. Dreyer; Rod G. Sinks; Kurt A. Stoll
- Web page: https://patentgrep.com/patent/US5347549A

## CPC

- H04L 25/20: Repeater circuits; Relay circuits
- H04L 5/1461: {Suppression of signals in the return path, i.e. bidirectional control circuits}
- H04L 25/02: Details {; arrangements for supplying electrical power along data transmission lines (systems for transmitting signals via power distribution lines H04B3/54)}
- H04L 25/0266: {Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling}
- H04L 25/0272: {Arrangements for coupling to multiple lines, e.g. for differential transmission}
- H04L 25/028: {Arrangements specific to the transmitter end}
- H04L 25/0292: {Arrangements specific to the receiver end}
- H04L 25/0264: {Arrangements for coupling to transmission lines (duplexing arrangements H04L5/14; line equalisers, line build-out devices H04L25/03878)}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A transceiver module for coupling between cells in a distributed intelligence network and a twisted pair line. The module receives power from the line and provides power to its respective cell. At the end of transmitting a packet, the transceiver transmits a code violation (pulse), then an anti-code violation (pulse of opposite polarity) to dissipate energy in the line. This is followed by clamping the line for the dead time between packets. N transceivers may be connected (without a cell) to form a repeater. The transceiver module may be used in a network having free topology; that is, an ideal transmission line, with terminators is not needed.

## Claims

### Claim 1

In a network having a plurality of nodes interconnected by a line where communications occur by transmitting packets over the line and where the end of a packet is signified by the transmission of a first pulse having a predetermined duration and a polarity, an improved method comprising the steps of:
transmitting onto the line a second pulse following the first pulse, the second pulse being of an opposite polarity to the first pulse and having a duration approximately equal to the predetermined duration of the first pulse; and,
following the second pulse, clamping the line.

### Claim 2 (depends on 1)

The method defined by claim 1 wherein the clamping is terminated before the next packet is transmitted.

### Claim 3 (depends on 2)

The method defined by claim 2 wherein the transmitting onto the line occurs from a pair of terminals and the clamping comprises connecting together the pair of terminals.

### Claim 4

A method for reducing unwanted charge on a line in a network where data is transmitted in packets over the line, comprising the steps of;
transmitting an ending pulse at the end of a packet, the ending pulse having a duration longer than durations of pulses used for transmitting data within the packets, the ending pulse having a polarity;
following the ending pulse, transmitting an additional pulse having a polarity opposite to that of the ending pulse and having a duration approximately equal to the duration of the ending pulse.

### Claim 5 (depends on 4)

The method defined by claim 4 wherein the transmitting steps occur from a pair of terminals and the method comprises an additional step of connecting together the pair of terminals following said additional pulse.

### Claim 6

In an apparatus for transmitting data packets in a network, the method comprising the steps of;
transmitting an ending pulse at the end of a packet, the ending pulse having a duration longer than durations of pulses used to represent data within the packets, the ending pulse having a polarity;
following the ending pulse, transmitting an additional pulse having a polarity opposite to that of the ending pulse and having a duration approximately equal to the duration of the ending pulse.

### Claim 7 (depends on 6)

The method defined by claim 6 including the step of clamping lines in the network.

### Claim 8 (depends on 7)

The method defined by claim 7 wherein the clamping comprises connecting the lines together.

### Claim 9

In a network having a plurality of nodes, each having a transceiver and a cell, an improved method of operation comprising the steps of;
providing a powered-down signal from the cell to the transceiver upon the occurrence of a predetermined activity;
reducing power consumed in the node in response to powered-down signal;
reactivating power to the transceiver after a predetermined duration; and,
transmitting a reactivation signal to the cell.

### Claim 10 (depends on 9)

The method defined by claim 9 wherein the predetermined activity is the completion of a function performed by the cell.

### Claim 11 (depends on 10)

The method defined by claim 10 wherein the predetermined duration is selectable.

### Claim 12 (depends on 11)

The method defined by claim 11 wherein the selectability of the duration comprises the step of connecting a capacitor at a terminal of the transceiver.