Browse Prior Art Database

Keyset to Transmission Line Encoder

IP.com Disclosure Number: IPCOM000094541D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Friedrich, AA: AUTHOR [+3]

Abstract

A multiplicity of key positions can serially transmit.code information over a relatively small number of transmission lines by using combinations of positive, negative and zero voltage levels.

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Keyset to Transmission Line Encoder

A multiplicity of key positions can serially transmit.code information over a relatively small number of transmission lines by using combinations of positive, negative and zero voltage levels.

Each key position 1...9, 0, R and S at a keyset are manually operable to close a normally open contact such as 11 and concurrently open a normally closed contact such as 12. A greater or lesser number of keys than shown can be used. The keys can represent any number of numerals, letters, functions or combinations of these. As shown, actuation of a key causes one, two or three of relays 20...24 to be energized from power source +V through the then closed vertical contact to ground. This operation causes various combinations of normally open contacts 25...29 of 20...24 to place +V, -V or zero potentials upon transmission lines 31, 32 and 33 which terminate in remote detector 30.

Within 30 is an arrangement including two pairs of serially connected relay coils 35 and 36 and 37 and 38 with each pair having oppositely polled diodes such as 40 and 41 connected in parallel. Thus, with +V on line 31, diode 40 is forward biased effectively bypassing relay 35 while diode 41 is reverse biased causing selection of relay 36. Conversely, tV at 31 selects 35 and bypasses 36. The relays and diodes connected to line 32 operate similarly. The relay connected to line 33 is only sensitive to a negative potential in the exemplary system shown.

To illustrate t...