US5349635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Half-duplex or full-duplex automode operation for use in data communications equipment
Assignee: Nokia Bell Labs
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Filing: 1992-11-19
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Granted: 1994-09-20
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Expires: 2012-11-19
Abstract
Abstract A V.32 compatible modem provides a full-duplex mode of operation, while a 208B compatible modem provides a half-duplex mode of operation. The connect sequence of a V.32 compatible modem is modified so that it will automatically determine if the other modem, whether the originating modem or the answering modem, is a 208B type of modem or a V.32 type of modem. In one embodiment of the invention, the connect sequence of an originating V.32 modem is modified to detect either a 2100 Hz answer tone, which represents that the answering modem is a V.32 type of modem, or a 2021 Hz answer tone, which represents that the answering modem is a 208B type of modem. In another embodiment of the invention, the connect sequence of an answering V.32 modem is modified to transmit first a 2100 Hz answer tone and then, if no 1800 Hz V.32 signal "AA" is received from the originating modem, to transmit a 2021 Hz answer tone, thereby simulating a 208B modem has answered the data call. In either case, once the identity of the other modem is determined, this modified modem will then switch to either a half-duplex mode or a full-duplex mode of operation as appropriate.
Inventors
- 👤 Robert E. Scott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:11
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/06; H04L; H04L5/00; H04L5/14
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
154 words
A method for originating a data call for use in data communications equipment, the method comprising the steps of: a) placing a telephone call to a called party; b) detecting an answer tone from an answering data communications equipment of the called party, where the answer tone comprises a single frequency; and c) switching to one of a number of operating modes as a function of the frequency of the detected answer tone; where the one of the number of operating modes is a full-duplex mode and another one of the number of operating modes is a half-duplex mode, and where said full-duplex operating mode is selected if the frequency of the detected answer tone is at a first frequency and where the half-duplex operating mode is selected if the frequency of the detected answer tone is at a second frequency, where the first frequency and the second frequency are different from each other.
Claim 2
Independent Claim
154 words
A method for originating a data call for use in data communications equipment, the method comprising the steps of: a) placing a telephone call to a called party; b) detecting an answer tone from an answering data communications equipment of the called party, where the answer tone comprises a single frequency; and c) switching to one of a number of operating modes as a function of the frequency of the detected answer tone; where the one of the number of operating modes is a full-duplex mode and another one of the number of operating modes is a half-duplex mode, and where said full-duplex operating mode is selected if the frequency of the detected answer tone is at a first frequency and where the half-duplex operating mode is selected if the frequency of the detected answer tone is at a second frequency, where the first frequency and the second frequency are different from each other.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the full-duplex mode is a V.32 mode of operation and the first frequency is 2100 Hz, and the half-duplex mode is a 208B mode of operation and the second frequency is 2021 Hz.
Claim 4
Independent Claim
162 words
A method for originating a data call for use in data communications equipment, the method comprising the steps of: a) placing a telephone called to a called party; b) detecting an answer tone from an answering data communications equipment of the called pray, where the answer tone comprises a single frequency; and c) switching to one of a number of operating modes as a function of the frequency of the detected answer tone; where the one of the number of operating modes is a full-duplex mode and another one of the number of operating modes is a half-duplex mode, and where said full-duplex operating mode is selected if the frequency of the detected answer tone is within a first narrow frequency band and where the half-duplex operating mode is selected if the frequency of the detected answer tone is within a second narrow frequency band, where the first narrow frequency band and the second narrow frequency band are different from each other.
Claim 5
Independent Claim
162 words
A method for originating a data call for use in data communications equipment, the method comprising the steps of: a) placing a telephone called to a called party; b) detecting an answer tone from an answering data communications equipment of the called pray, where the answer tone comprises a single frequency; and c) switching to one of a number of operating modes as a function of the frequency of the detected answer tone; where the one of the number of operating modes is a full-duplex mode and another one of the number of operating modes is a half-duplex mode, and where said full-duplex operating mode is selected if the frequency of the detected answer tone is within a first narrow frequency band and where the half-duplex operating mode is selected if the frequency of the detected answer tone is within a second narrow frequency band, where the first narrow frequency band and the second narrow frequency band are different from each other.
Claim 6
Dependent Claim
43 words
The method of claim 3 wherein the full-duplex mode is a V.32 mode of operation and the first narrow frequency band includes 2100 Hz, and the half-duplex mode is a 208B mode of operation and the second narrow frequency band includes 2021 Hz.
Claim 7
Independent Claim
160 words
A method for answering a data call for use in data communications equipment, the method comprising the steps of: a) answering a data call from a calling party; b) providing a first signal comprising a single frequency to a communications channel for transmission to the calling party, the first signal having a duration of T 1 seconds; c) providing a second signal comprising a single frequency to the communications channel for transmission to the calling party, the second signal having a duration of T 2 seconds, where the time duration of T 2 occurs subsequent to the time duration of T 1 ; d) waiting for a period of time, T 3 seconds, where the time duration of T 3 occurs subsequent to the time duration of T 2 ; and e) following step d, switching to a half-duplex mode of operation for controlling the transmitting and receiving of information to and from the calling party over the communications channel.
Claim 8
Independent Claim
160 words
A method for answering a data call for use in data communications equipment, the method comprising the steps of: a) answering a data call from a calling party; b) providing a first signal comprising a single frequency to a communications channel for transmission to the calling party, the first signal having a duration of T 1 seconds; c) providing a second signal comprising a single frequency to the communications channel for transmission to the calling party, the second signal having a duration of T 2 seconds, where the time duration of T 2 occurs subsequent to the time duration of T 1 ; d) waiting for a period of time, T 3 seconds, where the time duration of T 3 occurs subsequent to the time duration of T 2 ; and e) following step d, switching to a half-duplex mode of operation for controlling the transmitting and receiving of information to and from the calling party over the communications channel.
Claim 9
Dependent Claim
16 words
The method of claim 5 where the time interval T 3 is at least 63 milli-seconds.
Claim 10
Dependent Claim
49 words
The method of claim 6 wherein the first signal is a V.32 answer tone having a single frequency of 2100 Hz and the second signal is a 208B answer tone having a signal frequency of 2021 Hz, and the half-duplex mode of operation is a 208B mode of operation.
Claim 11
Dependent Claim
129 words
Apparatus for use in data communications equipment comprising: means responsive to a ringing signal from a communications channel for answering a telephone call from an originating modem and for providing a first signal which represents that the telephone call has been received; and means responsive to the first signal for a) generating a sequence of tones for transmission to the originating modem over the communications channel, where the first tone of the sequence is at a first frequency with a duration of T 1 seconds, where the second tone of the sequence is at a second frequency with a duration of T 2 seconds followed by a silent period of T 3 seconds, and for b) switching to a half-duplex mode of operation after said T 3 time interval.
Claim 12
Dependent Claim
129 words
Apparatus for use in data communications equipment comprising: means responsive to a ringing signal from a communications channel for answering a telephone call from an originating modem and for providing a first signal which represents that the telephone call has been received; and means responsive to the first signal for a) generating a sequence of tones for transmission to the originating modem over the communications channel, where the first tone of the sequence is at a first frequency with a duration of T 1 seconds, where the second tone of the sequence is at a second frequency with a duration of T 2 seconds followed by a silent period of T 3 seconds, and for b) switching to a half-duplex mode of operation after said T 3 time interval.
Claim 13
Dependent Claim
16 words
The apparatus of claim 8 wherein the time interval T 3 is at least 63 milli-seconds.
Claim 14
Dependent Claim
46 words
The apparatus of claim 11 wherein the first tone is a V.32 answer tone with a frequency of 2100 Hz, the second tone is a 208B answer tone with a frequency of 2021 Hz, and the half-duplex mode of operation is a 208B mode of operation.
Claim 15
Dependent Claim
74 words
Apparatus for use in data communications equipment comprising: means for receiving an answer tone signal from a communications channel, the answer tone signal comprising a single frequency; and means for determining whether the received answer tone signal comprises a first predetermined frequency or a second predetermined frequency and for providing a determination signal; and means responsive to the determination signal for switching between a full-duplex mode of operation and a half-duplex mode of operation.
Claim 16
Dependent Claim
74 words
Apparatus for use in data communications equipment comprising: means for receiving an answer tone signal from a communications channel, the answer tone signal comprising a single frequency; and means for determining whether the received answer tone signal comprises a first predetermined frequency or a second predetermined frequency and for providing a determination signal; and means responsive to the determination signal for switching between a full-duplex mode of operation and a half-duplex mode of operation.
Claim 17
Dependent Claim
37 words
The apparatus of claim 11 wherein the predetermined first frequency is 2100 Hz, the predetermined second frequency is 2021 Hz, the full-duplex mode is a V.32 compatible mode, and the half-duplex mode is a 208B compatible mode.
Claim 18
Dependent Claim
122 words
Data communications equipment apparatus comprising: means for receiving an answer tone from a communications channel from an answering modem; multi-modulation means for providing one of two modulation schemes, where one of said modulation schemes has a transmission rate of 4800 bits/second and is half-duplex and the other modulation scheme has a transmission rate of at least 9600 bits/second and is full-duplex; and means for selecting one of the two modulation schemes as a function of the received answer tone, where the 4800 bits/second half-duplex modulation scheme is selected if the received answer tone has a frequency of 2021 Hz and where the at least 9600 bits/second full-duplex modulation scheme is selected if the received answer tone has a frequency of 2100 Hz.
Claim 19
Dependent Claim
122 words
Data communications equipment apparatus comprising: means for receiving an answer tone from a communications channel from an answering modem; multi-modulation means for providing one of two modulation schemes, where one of said modulation schemes has a transmission rate of 4800 bits/second and is half-duplex and the other modulation scheme has a transmission rate of at least 9600 bits/second and is full-duplex; and means for selecting one of the two modulation schemes as a function of the received answer tone, where the 4800 bits/second half-duplex modulation scheme is selected if the received answer tone has a frequency of 2021 Hz and where the at least 9600 bits/second full-duplex modulation scheme is selected if the received answer tone has a frequency of 2100 Hz.
References Cited (Backward Citations)
US4215243A
Cited
US4471489A
Cited
US4599719A
Cited
US4680773A
Cited
US4782498A
Cited
US4931250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-19 | 1998-03-21 | 1998-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-19 | 2002-03-21 | 2002-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-19 | 2006-03-21 | 2006-09-20 | $7700.00 | Window Closed / Lapsed |