Browse Prior Art Database

Telephone System Line Control Terminal

IP.com Disclosure Number: IPCOM000086296D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Chu, PT: AUTHOR [+4]

Abstract

This terminal facilitates attendant supervision of a number of line appearances, by direct communication with a telephone exchange independently of those lines.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Telephone System Line Control Terminal

This terminal facilitates attendant supervision of a number of line appearances, by direct communication with a telephone exchange independently of those lines.

As shown in the diagram, terminal 8 includes a basic push button (PB) and lamp unit to permit an attendant to respond to calls on a number of extensions. The basic unit has eight lamp/PB pairs 10, 12 (one attendant and seven extensions), a hold PB 14 and an audible signal 16. It is extendable by the addition of three additional PB/lamp modules, each constituting a group of eight lamp/PB pairs. The basic and each additional module are separately addressable.

Signals received at the interface 18 from a computer controlled exchange, not shown, are decoded to activate a lamp 12 in one of six possible modes (on, off, wink, blink, quick flash, and reset), and also to control signal 16. Depression of a PB 10, 14 results in the generation of a coded signal which is sent via interface 20 to the attendant's extension line 22.

The digital input to terminal 8 at interface 18 is in the form of frequency-shift keyed (FSK) signals. The output of terminal A at line 22 is in the form of multifrequency (MF) signals in CCITT A, B form. terminal 8 accesses line 22 via transfer switch 26.

Signals from line 28 are demodulated at 30, deserialized at 32 and decoded at 34. Timing for this operation is provided by the FSK sequencer 36 which is operated by an oscillator 38 driven clock 40 after being initiated by a start bit via line 42. Up to sixteen, eight appearance control modules can share a single distribution line 28. The number of the module is assigned by the setting of switches in configuration control 44. This scheme of addressing may be of the kind described in the IBM Technical Disclosure Bulletin, Vol. 17, No. 3, August, 1974, pages 841 - 842.

Bits O-3 and 4-6 of the FSK message identify the module number and lamp number, respectively, so as to constitute a lamp address. Bits 7-9 provide the operation code (OP). When decoder 34 recognizes a module number associated with its terminal, by comparing with control 44, it allows mode controls 46 to set the...