Title:
KEY TELEPHONE DEVICE
Document Type and Number:
WIPO Patent Application WO/1991/011888
Kind Code:
A1
Abstract:
A key telephone device in which ports for connecting terminals are of a 2-pair (4-wire) type, one pair (two-wire) is connected to digital terminals and the other (two-wire) connected to analog terminals together, and which has a change-over controlling means by which an interface circuit for the analog terminals and an interface circuit for the digital terminal both connected to the ports are changed over automatically according to the working condition of the terminals. Therefore, an analog terminal of one-pair type and a digital terminal of one-pair type can be connected to one port together. Since the interface circuits for analog and digital terminals can be changed over under the supervision of change-over controlling means according to the working condition of the terminals, the analog and digital terminals can be handled as one terminal (an extension).
Inventors:
HAYASHI TAKASHI (JP)
Application Number:
PCT/JP1991/000095
Publication Date:
August 08, 1991
Filing Date:
January 29, 1991
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD (JP)
International Classes:
H04Q3/58; H04M1/71; H04M9/00; H04Q3/42; (IPC1-7): H04Q3/58
Foreign References:
| JPS6477399A | 1989-03-23 | |||
| JPS63290488A | 1988-11-28 |
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