Title:
TELEPHONE SYSTEM WITH ANSWERING MACHINE
Document Type and Number:
WIPO Patent Application WO1999022506
Kind Code:
A3
Abstract:
The present invention relates to a telephone system (1) comprising at least one telephone subset (3) and an answering machine (5) which are connected, in parallel, to an outside telephone line (9). The system (1) has a first line terminal (11) and a second line terminal (13). The answering machine (5) comprises tone-generating means (37) for generating a probe tone from the answering machine (5) to the first and second line terminals (11, 13). The system (1) further comprises detection means (41, 43, 45) for detecting a change in reflected residue of said tone in response to an impedance change between the telephone system (1) and the outside telephone line (9).
Inventors:
STIPHOUT EDUARD HENRI
MENNEN MARTINUS ERNASTINUS JEA
MENNEN MARTINUS ERNASTINUS JEA
Application Number:
PCT/IB1998/001656
Publication Date:
August 12, 1999
Filing Date:
October 19, 1998
Export Citation:
Assignee:
KONINKL PHILIPS ELECTRONICS NV (NL)
PHILIPS SVENSKA AB (SE)
PHILIPS SVENSKA AB (SE)
International Classes:
H04M1/00; H04M1/64; H04M1/65; H04M1/654; H04M1/72; H04W4/16; H04W88/02; (IPC1-7): H04M1/64; H04M1/65; H04M1/72
Foreign References:
| DE3011758A1 | 1981-10-01 | |||
| US5392332A | 1995-02-21 | |||
| US5481596A | 1996-01-02 | |||
| US5579377A | 1996-11-26 |
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