EP0180066A2
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EP
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Multidrop modem communication system
Assignee: Universal Data Systems Inc
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Filing: 1985-10-07
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Granted: —
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Expires: 2005-10-07
Abstract
Abstract A multidrop high-speed modem communication system having a master and a plurality of remote modems, wherein an initial long train sequence provides the necessary modem equalization, wherein subsequent channel communications are preceded by a short training sequence. The remote modems, operating as slave modems, include a transmitter pre-equalizer, wherein the equalizer coefficients for each remote-to-master channel are generated at the master modem and sent to the remote modems. Upon subsequent communications, a slave modem reloads the previous coefficients for its channel into its transmitter equalilizer. Other modem parameters, such as timing, phase, and frequency are reestablished by a short fast train sequence. Thereby, the modems may quickly exchange data without consuming excessive time in equalizing the channel for each remote-to-master transmission.
Inventors
- 👤 Richard A. Burch
- 👤 Dennis B. Mcmahan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 12:41
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/403; H04L12/40006; H04L12/40032; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03114; H04L25/03133; H04L25/03343; H04L2025/03777; H04L2025/03802; H04L2025/03808
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
189 words
A method of establishing a communications channel between a master modem and one of a plurality of remote modems and associated data terminal equipment, comprising the steps of: transmitting an address from the master corresponding to one of the data terminal equipment of the respective remote modems to said plurality of remote modems; receiving said address by each said remote modem; identifying said address by the data terminal equipment having said address wherein a request to send signal is generated; transmitting an acknowledgement signal from one of said plurality of remote modems according to request to send signal; receiving said acknowledgement by said master modem; selectively transmitting a long train sequence from said remote modem; receiving said long train sequence at the master modem receiving the request to send signal; adjusting the equalizer coefficients at said master modem; transmitting said equalizer coefficient from said master modem to said remote modem; receiving said coefficients from said master modem by said remote modem; storing said equalizer coefficients in said remote modem; equalizing the subsequently transmitted signals from the remote modem; and transmitting a data flow between said master and remote modems.
Claim 2
Independent Claim
189 words
A method of establishing a communications channel between a master modem and one of a plurality of remote modems and associated data terminal equipment, comprising the steps of: transmitting an address from the master corresponding to one of the data terminal equipment of the respective remote modems to said plurality of remote modems; receiving said address by each said remote modem; identifying said address by the data terminal equipment having said address wherein a request to send signal is generated; transmitting an acknowledgement signal from one of said plurality of remote modems according to request to send signal; receiving said acknowledgement by said master modem; selectively transmitting a long train sequence from said remote modem; receiving said long train sequence at the master modem receiving the request to send signal; adjusting the equalizer coefficients at said master modem; transmitting said equalizer coefficient from said master modem to said remote modem; receiving said coefficients from said master modem by said remote modem; storing said equalizer coefficients in said remote modem; equalizing the subsequently transmitted signals from the remote modem; and transmitting a data flow between said master and remote modems.
Claim 3
Dependent Claim
25 words
The method of claim 1, wherein said step of selectively transmitting a long train sequence includes the step of detecting a long train request signal.
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein said step of detecting a long train request signal comprises receiving a long train request tone.
Claim 5
Dependent Claim
119 words
The method of claim 1, further comprising the steps of: terminating the data flow; polling the remote modems by said master modem, wherein the address corresponding to a previously addressed data terminal equipment is transmitted; receiving said address by said data terminal equipment; identifying said address by said data terminal equipment, causing a request to send signal to be generated; transmitting an acknowledgement signal from the master modem corresponding to the modem receiving said request to send signal; receiving said acknowledge signal; selectively transmitting a short train sequence from said remote; receiving said short train sequence at the master modem; adjusting the receiver of the master modem; and commencing the exchange of data between the master and remote modem.
Claim 6
Dependent Claim
26 words
The method of claim 4, wherein 4 said step of selectively transmitting a short train sequence comprises the step of detecting a short train request signal.
Claim 7
Dependent Claim
22 words
The method of claim 5, wherein said step of detecting a short train request signal comprises receiving a short train request tone.
Claim 8
Dependent Claim
102 words
A multidrop modem communication system, comprising: a bidirectional communication line; a master modem, including: a receiver having an equalizer therein and having characteristics represented by corresponding equalizer coefficients; and a transmitter having means to transmit said master receiver equalizer coefficients; and at least one remote modem, including: a transmitter connected to communicate with said master modem receiver over said communication lines, including a transmit equalizer; and a receiver connected to communicate with said master modem receiver over said communication lines including means to adjust said transmit equalizer according to said received equalizer cofficient; wherein additional remote receiver parameters are locally acquired thereafter.
Claim 9
Dependent Claim
102 words
A multidrop modem communication system, comprising: a bidirectional communication line; a master modem, including: a receiver having an equalizer therein and having characteristics represented by corresponding equalizer coefficients; and a transmitter having means to transmit said master receiver equalizer coefficients; and at least one remote modem, including: a transmitter connected to communicate with said master modem receiver over said communication lines, including a transmit equalizer; and a receiver connected to communicate with said master modem receiver over said communication lines including means to adjust said transmit equalizer according to said received equalizer cofficient; wherein additional remote receiver parameters are locally acquired thereafter.
Claim 10
Dependent Claim
43 words
The multidrop modem communication system of claim 7, wherein at least one of said master modem and remote modem includes timing training means including at least one of: means for generating a long train sequence; and means for generating a short train sequence.
Claim 11
Dependent Claim
51 words
The multidrop modem communication system of claim 8, wherein at least one other of said master modem and remote modem includes: sequence request means providing a signal to the corresponding one of said long train and short train; and means for selectively receiving said long train and said short train sequence.
Claim 12
Dependent Claim
70 words
The multidrop modem communication system of claim 9, wherein said long train sequence is initially selected wherein the equalizer coefficients are selected, the respective said modem in communication therewith further including means to store said coefficients ar.d being operable to store said coefficients after said long train sequence, wherein said coefficients are reapplied for subsequent communications between respective modems for which said short train sequence is requested and thereafter generated.
Claim 13
Dependent Claim
134 words
A microprocessor controlled modem comprising: a first microprocessor having a data port signal and a counter output and respectively providing data and a serial vector output therefrom; a second microprocessor having a data port for receiving data therein, a counter having a counter input, and a vector interrupt means wherein said received data is selectively processed by said second microprocessor; first means for transferring data between said data ports of said first and said second microprocessors; and second means for transferring said serial vector output signal from said first microprocessor counter output to said second microprocessor counter input, wherein said second microprocessor vector interrupt means is operable according to the state of said counter to process said data received from said first microprocessor according to the serial vector output provided by said first microprocessor.
Claim 14
Dependent Claim
134 words
A microprocessor controlled modem comprising: a first microprocessor having a data port signal and a counter output and respectively providing data and a serial vector output therefrom; a second microprocessor having a data port for receiving data therein, a counter having a counter input, and a vector interrupt means wherein said received data is selectively processed by said second microprocessor; first means for transferring data between said data ports of said first and said second microprocessors; and second means for transferring said serial vector output signal from said first microprocessor counter output to said second microprocessor counter input, wherein said second microprocessor vector interrupt means is operable according to the state of said counter to process said data received from said first microprocessor according to the serial vector output provided by said first microprocessor.
Claim 15
Dependent Claim
21 words
The microprocessor controlled modem of claim 11, wherein said second microprocessor receives said data and said serial pulse output signal simultaneously.
Claim 16
Dependent Claim
41 words
The microprocessor controlled modem of claim 11, further including means to provide an acknowledge signal connected to said first microprocessor and said second microprocessor, wherein an acknowledge signal is provided after receipt of said serial vector signal by said second microprocessor.
Claim 17
Dependent Claim
26 words
The microprocessor controlled modem of claim 10, further including a modem receiver connected to said first microprocessor; and a modem transmitter connected to said second microprocessor.
Claim 18
Dependent Claim
61 words
The microprocessor controlled modem of claim 14 wherein said modem receiver includes an equalizer and is operable to provide selectable equalizer coefficients; said first microprocessor is adapted to transfer said equalizer coefficients as data wherein said data is identified according to said serial vector output signals; and said second microprocessor is adapted to transfer said data to said transmitter for transmission.
Claim 19
Dependent Claim
71 words
The microprocessor controlled modem of claim 13, wherein said modem receiver is operable to receive selectable equalizer coefficients; said first microprocessor is adapted to transfer said equalizer coefficients to said second microprocessor as data, wherein said data is identified according to said serial vector output signals, said transmitter includes an adjustable equalizer; and said second microprocessor is adapted to adjust said transmitter and said equalizer according to said received equalizer coefficients.
References Cited (Backward Citations)
No citation records indexed.
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