Northern Telecom Limited

Steven Kos

David R Baraff

William D Westwood

Christopher Henry Becker

Leonard George Bleile

Herman W Willemsen

Hussein M Naguib

When two or more telephone sets are in use on the same subscriber's loop, their activities may not be properly detected or monitored by the central office switch. The present invention provides a method of and an apparatus for coordinating activities so that call waiting caller ID or off-hook caller ID or other service features can work even if there are off-hook extensions on the same loop. The invention ensures that only one set among a plurality of off-hook sets responds to the switch.

Coordinating telephones or adjuncts on the same loop

A terminal has a reciprocating print head bearing a series of linearly arranged, individually-magnetizable styli for printing on magnetic particle oriented paper. The terminal may be used as a printer, or as a display by combining the printer with an erasing head comprising a series of linearly arranged magnets which create a rotating magnetic field to erase the magnetic particle oriented paper when the erasing head is reciprocated. The print and erase heads are mounted on a common carriage. The terminal is cheap to manufacture and, if used as a printer, has the advantage of reusable paper. If used as a display, it required no refresh.

Read/write arrangement for a magnetic terminal

A printer has a print head on which a series of individually-heatable printing resistors are linearly arranged. The print head is mounted on a carriage for stepwise reciprocation in a direction parallel to the line of resistors, paper being stepwise movable in a transverse direction. The printing sequence is designed to permit the carriage stepping motor to be operating in the slew mode for maximizing print speed.

Thermal printer

A photoconductive device for imaging a linear object has a plurality of photoconductive elements, extending in a line, on a substrate, with first and second patterns of electrical conductors, a pattern on each side of the line. Connections are made to the elements. The conductor patterns are formed as columns on one side of the line and as rows on the other side to provide connections between columns and elements and rows and elements such that the number of external connections is minimized. By applying a voltage to a column, and then connecting a detector current sequentially to each row, and repeating for each column, the current flowing through each element can be determined and a signal generated related to the illumination of each element. The elements can be a continuous bar of photoconductive material.

Photoconductor device for imaging a linear object

Each thick film resistive print element of a thermal print bar operated in a scan mode is series connected to a thick film switch which sets a voltage threshold to isolate the element from periodic scan pulses unless coincident with an element selecting data pulse in which case the thick film undergoes joule heating which causes it to switch and its series-connected resistive element undegoes joule heating.

Thermal printers

Instead of imaging a line across a document by a lens system on to an imager, direct imaging is obtained by positioning the document in close proximity to but spaced a predetermined distance from a linear array of photo-detectors and illuminating the document by light from beneath the detectors, the light passing through spaces between detectors and being reflected back to the detectors. To prevent saturation of the dectectors by light direct from the illuminating means, opaque material is positioned beneath the detectors with gaps or apertures through which light can illuminate the document. The detectors can be spaced close together to give desired resolution, or spaced a predetermined distance apart and the detector head stepped laterally. More than one line of detectors can be provided.

Direct imaging apparatus for an electronic document transmitter

A drive circuit for a matrix coupled thermal printing bar which permits the address of large arrays as would be used in a thermal facsimile printing system without the necessity for individually driving each element or providing isolated diodes to prevent leakage paths. The circuit utilizes the application of an intermediate voltage to the unaccessed rows or columns to limit the applied power to the unaccessed elements below that required to raise them to printing temperatures.

Growing community of inventors

Ottawa, Canada

Steven Kos