US5345437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for controlling frequency multiplexing modems
Assignee: Fujitsu Ltd
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Filing: 1993-05-07
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Granted: 1994-09-06
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Expires: 2013-05-07
Abstract
Abstract A frequency multiplexing control system includes a first modem unit connected to a transmission line, and a second modem unit connected to the transmission line. The first and second modem units communicate with each other via a plurality of primary channels and a secondary channel. The primary and secondary channels have different frequency bands. A plurality of signal detection units are respectively provided in the first and second modem units, to detect an abnormal primary channel and send to the second and first modem units, information concerning the abnormal primary channel via the secondary channel. A plurality of disabling units are respectively provided in the first and second modem units, to disable the abnormal primary channel in response to the received information and to send a training signal for recovering the abnormal primary channel to the transmission line.
Inventors
- 👤 Tohru Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:44
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/02; H04L5/06; H04L7/00; H04L7/0008
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
A frequency multiplexing control system comprising: a first modem unit connected to a transmission line; a second modem unit connected to said transmission line, the first and second modem units communicating with each other via a plurality of primary channels; a secondary channel provided between the first and second modem units, the secondary channel having a frequency band lower than frequency bands of the primary channels; a plurality of first means, respectively provided in the first and second modem units, for detecting an abnormal primary channel and sending to the second and first modem units information concerning the abnormal primary channel via the secondary channel; and a plurality of second means, respectively provided in the first and second modem units, for disabling the abnormal primary channel in response to said information and for sending a training signal for recovering the abnormal primary channel to the transmission line, via the secondary channel.
Claim 2
Dependent Claim
151 words
A frequency multiplexing control system comprising: a first modem unit connected to a transmission line; a second modem unit connected to said transmission line, the first and second modem units communicating with each other via a plurality of primary channels; a secondary channel provided between the first and second modem units, the secondary channel having a frequency band lower than frequency bands of the primary channels; a plurality of first means, respectively provided in the first and second modem units, for detecting an abnormal primary channel and sending to the second and first modem units information concerning the abnormal primary channel via the secondary channel; and a plurality of second means, respectively provided in the first and second modem units, for disabling the abnormal primary channel in response to said information and for sending a training signal for recovering the abnormal primary channel to the transmission line, via the secondary channel.
Claim 3
Dependent Claim
94 words
The frequency multiplexing control system as claimed in claim 1, wherein: said first modem unit comprises master clock generating means for generating a master clock signal and sending a timing signal related to the master clock signal to the second modem unit via the secondary channel; and said second modem unit comprises clock extracting means for extracting the timing signal sent via the secondary channel and for generating a slave clock signal which is the same as the master clock signal, and wherein the second modem unit is synchronized with the first modem unit.
Claim 4
Dependent Claim
55 words
The frequency multiplexing control system as claimed in claim 2, wherein: the first modem unit comprises a plurality of modems operating in synchronism with the master clock signal; and the second modem unit comprises a plurality of modems operating in synchronism with the slave clock signal which is the same as the master clock signal.
Claim 5
Dependent Claim
68 words
The frequency multiplexing control system as claimed in claim 2, wherein: the first modem unit comprises first conversion means for performing digital-to-analog and analog-to-digital operations on signals to be transmitted to the second modem unit and signals received therefrom; and the second modem unit comprises second conversion means for performing digital-to-analog and analog-to-digital operations on signals to be transmitted to the first modem unit and signals received therefrom.
Claim 6
Dependent Claim
28 words
The frequency multiplexing control system as claimed in claim 1, wherein the frequency band of the secondary channel is lower than the frequency bands of the primary channels.
Claim 7
Dependent Claim
40 words
The frequency multiplexing control system as claimed in claim 1, which comprises n second modem units where n is an integer equal in number to the primary channels; wherein the n second modem units are connected to the transmission line.
Claim 8
Dependent Claim
33 words
The frequency multiplexing control system as claimed in claim 6, wherein each of the second modem units accommodates a terminal connected to the transmission line via a different one of the primary channels.
Claim 9
Dependent Claim
23 words
The frequency multiplexing control system as claimed in claim 1, wherein the second modem unit accommodates terminals respectively provided for the primary channels.
Claim 10
Dependent Claim
19 words
The frequency multiplexing control system as claimed in claim 1, wherein the transmission line is an analog transmission line.
Claim 11
Dependent Claim
190 words
The frequency multiplexing control system as claimed in claim 1, wherein: said first modem unit comprises master clock generating means for generating a master clock signal and sending a timing signal related to the master clock signal to the second modem unit via the secondary channel; said second modem unit comprises clock extracting means for extracting the timing signal sent via the secondary channel and for generating a slave clock signal which is the same as the master clock signal; the second modem unit is synchronized with the first modem unit; the first modem unit comprises a plurality of modems operating in synchronism with the master clock; the second modem unit comprises a plurality of modems operating in synchronism with the slave clock signal which is the same as the master clock signal; the first modem unit comprises first conversion means for performing digital-to-analog and analog-to-digital operations on signals to be transmitted to the second modulation unit and signals received therefrom; and the second modem unit comprises second conversion means for performing digital-to-analog and analog-to-digital operations on signals to be transmitted to the first modem unit and signals received therefrom.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-05 | 1998-03-07 | 1998-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-05 | 2002-03-07 | 2002-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-05 | 2006-03-07 | 2006-09-06 | $7700.00 | Window Closed / Lapsed |