4554413 Key telephone system

r ~ i idl¢lll i g l i ii i i ~ i . i I i ~

PATSEARCH

SECTION

NEW PATENTS This Section contains abstracts and. where appropriate, illustrations of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH ~ online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH" can be obtained from Pergamon InfoLine Inc., 1340 Old Chain Bridge Road, Mclean, Virginia 22101 U.S.A. Copies of complete patents announced in this Section are available from Pergamon Infoline Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon lnfoLine only. ,

4554410

.

~,~

. . . . . .

t

"t

i

~**~,,,,,%~

~"

SYSTEM FOR MAINTENANCE AND DIAGNOSIS OF MOBILE TELEPHONE EQUIPMENT Takayuk Furumoto, Yokohama, signed to Hitachi Ltd 15

!6

,13 i~ .

Japan as-

O~

A key telephone system uses four wires for transmission of voice and audio signals to and from the tdephone stations and other components which are part of the system. A plurality of telephone stations are provided, each having a two wire audio input port, a separate two wire audio output port, and a data port. Communcation paths are established through a crosspoint matrix. The matrix includes a first group of addressable crosspoint switches for coupling selected transmit signal paths to selected first link points. A second group of such switches is provided for coupling selected receive signal paths to selected second link points. A third group of such switches couples selected first link points to selected second link points. A link searching routine determines which links are available for effecting communication paths. A minimizing function shares communication paths among common signals when possible.

"rO~

c,Rculr

;

i ,~*ttt<[R

!

~5-~

#

For maintenance and diagnosis of mobile telephone equipment carried on a vehicle such as a car, ship or airplane, an input/output port of a control unit for effecting desired controlling and processing for individual parts of the mobile telephone equipment on the basis of stored program control is inputted with test mode information in the form of a logic signal supplied manually or a specified dial number signal supplied by dialing a telephone unit so as to switch the mobile telephone equipment to a test mode. Thereafter, a predetermined test instruction and a predetermined additional data are inputted to the input/output port by dialing the telephone unit. The control unit then reads the instruction and data to select and execute a desired, predetermined test program. A result of the execution is indicated on an indicator of the telephone unit for maintenance and diagnosis.

4554417 TANDEM ADAPTIVE ECHO CANCELER ARRANGEMENT Kim L Boyer Laboratories

4554413 KEY TELEPHONE

SYSTEM

to

AT&T

Bell

An extended impulse response characteristic is obtained by switchably connecting (via 13, 14, 15) at least first (10) and second (12) adaptive echo cancelers in a tandem connection (FIG. I).

Edouard Pinede, Serge Faublas, Peter Stevens assigned to PKS/Communications Inc TELEMATICS and INFORMATICS

assigned

Vol. 3, No. 2, pp. V-Xll, 1986 Copyright © 1986 Pergamon Journals Ltd. Printed in the U.S.A. 0736-5853•86 $3.00 + .00

V