US3840705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Data channel unit for a pcm tdm system
Assignee: Northeast Electronics Corp
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Filing: 1972-08-16
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Granted: 1974-10-08
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Expires: 1992-08-16
Abstract
Abstract A data terminal is disclosed, containing internal clocks, which is designed to replace conventional audio channel units of the D1 channel bank of the Bell System T1 carrier system, to permit the transmission of data.
Inventors
- 👤 W Haskett
- 👤 H Wochholz
- 👤 D Penick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:44
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/07
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
270 words
A data terminal for replacing a selected channel unit of a multiplex PCM carrier transmission system which has: a common transmission line; a plurality of transmitting channel units each providing a low rate bit stream buffered in an output buffer; a central channel clock and a channel switch responsive thereto for multiplexing the channel units by connecting the output buffer of each channel unit to the transmission line only during a channel pulse allotted to that channel unit; and a central data clock for clocking the contents of the output buffer connected to the transmission line at a high rate, to thereby transmit over said line a high rate multiplexed bit system; said data terminal having a transmitter comprising: means for generating a bit stream; means for buffering the bit stream; first internal clock means, distinct from said central clocks, for generating a first clock train; means for clocking the bit stream from the generating means into the buffering means at the frequency of said first clock train; second internal clock means, distinct from said central clocks, for generating a second pulse train at the frequency of the transmission line; means responsive to a selected channel pulse of the central channel clock for connecting the buffering means to the transmission line for the duration of the last recited pulse; means for clocking the contents of the buffering means onto the transmission line at the frequency of the second pulse train for the duration of said selected channel pulse; and means for synchronizing the first and second internal clock means with the frequency of at least one of said central clocks.
Claim 2
Dependent Claim
270 words
A data terminal for replacing a selected channel unit of a multiplex PCM carrier transmission system which has: a common transmission line; a plurality of transmitting channel units each providing a low rate bit stream buffered in an output buffer; a central channel clock and a channel switch responsive thereto for multiplexing the channel units by connecting the output buffer of each channel unit to the transmission line only during a channel pulse allotted to that channel unit; and a central data clock for clocking the contents of the output buffer connected to the transmission line at a high rate, to thereby transmit over said line a high rate multiplexed bit system; said data terminal having a transmitter comprising: means for generating a bit stream; means for buffering the bit stream; first internal clock means, distinct from said central clocks, for generating a first clock train; means for clocking the bit stream from the generating means into the buffering means at the frequency of said first clock train; second internal clock means, distinct from said central clocks, for generating a second pulse train at the frequency of the transmission line; means responsive to a selected channel pulse of the central channel clock for connecting the buffering means to the transmission line for the duration of the last recited pulse; means for clocking the contents of the buffering means onto the transmission line at the frequency of the second pulse train for the duration of said selected channel pulse; and means for synchronizing the first and second internal clock means with the frequency of at least one of said central clocks.
Claim 3
Dependent Claim
34 words
A data terminal as in claim 1 wherein the synchronizing means includes means for synchronizing the first and second internal clock means with the transmission rate of the bit stream on the transmission line.
Claim 4
Dependent Claim
39 words
A data terminal as in claim 1 wherein the first clock train from the first internal clock means is at approximately 56 KHz and the second pulse train from the second internal clock means is at approximately 1.544 MHz.
Claim 5
Dependent Claim
242 words
A data terminal as in claim 1 wherein the carrier system includes: a plurality of receiving channel units; a second central channel clock and a channel switch responsive thereto for demultiplexing the composite bit stream by connecting each receiving channel unit to the transmission line only during a channel pulse allotted to the receiving channel unit; and a second central data clock for clocking the bit stream carried by the transmission line into the channel units, and wherein the data terminal has a receiver comprising: an input buffer and a receiving unit; third internal clock means, distinct from said central clocks, for generating a third pulse train at the frequency of the bit stream on the transmission line; fourth internal clock means, distinct from said central clocks, for generating a fourth pulse train at a substantially lower frequency than the third pulse train; means responsive to a selected channel pulse of the second central channel clock for connecting the input buffer to the transmission line and for transferring into the input buffer the bit stream carried by the transmission line for the duration of said selected channel pulse, said transfer taking place at the frequency of said third clock pulse train; means for transferring the contents of the input buffer to the receiving unit at the frequency of said fourth clock pulse train; and means for synchronizing the third and fourth internal clock means with at least one of said central clocks.
Claim 6
Dependent Claim
33 words
A data terminal as in claim 4 wherein the last recited synchronizing means synchronizes the third and fourth iNternal clock means with the bit rate of the bit stream on the transmission line.
Claim 7
Dependent Claim
35 words
A data terminal as in claim 5 wherein the last recited synchronizing means includes means for connecting the third and fourth internal clock means with the transmission line for recovery of the transmission line frequency.
Claim 8
Dependent Claim
88 words
A data terminal as in claim 4 including testing means comprising: a test signal source; means for preventing the connection of the generating means to the buffering means and for connecting the test signal source to the buffering means to thereby cause the data terminal transmitter to apply said test signal to the transmission line; and detecting means at the receiver connected to the input buffer and responsive to the receipt of said test signal from the transmission line into the input buffer to provide an indication thereof.
Claim 9
Dependent Claim
250 words
A data terminal for replacing a channel unit of a PCM carrier system which includes: a transmission line carrying a multiplexed bit stream; a plurality of channel units; a central channel clock and a channel switch responsive thereto for demultiplexing the transmission line bit stream by connecting each of the channel units to the transmission line only during a channel pulse allotted to that channel unit; and a central data clock for clocking the bit stream from the transmission line into the channel unit connected thereto, said data terminal comprising: an input buffer and a receiving unit; first internal clock means, distinct from said central clocks, for generating a first pulse train at the frequency of the bit stream on the transmission line; second internal clock means, distinct from said central clocks, for generating a second pulse train at a substantially lower frequency than the first pulse train; means responsive to a selected channel pulse of the central channel clock for connecting the input buffer to the transmission line and for transferring into the input buffer the bit stream carried by the transmission line for the duration of said selected channel pulse, said transfer taking place at the frequency of said first clock pulse train; means for transferring the contents of the input buffer to the receiving unit at the frequency of said second clock pulse train; and means for synchronizing the first and second internal clock means with the bit rate of the bit stream on the transmission line.
Claim 10
Dependent Claim
250 words
A data terminal for replacing a channel unit of a PCM carrier system which includes: a transmission line carrying a multiplexed bit stream; a plurality of channel units; a central channel clock and a channel switch responsive thereto for demultiplexing the transmission line bit stream by connecting each of the channel units to the transmission line only during a channel pulse allotted to that channel unit; and a central data clock for clocking the bit stream from the transmission line into the channel unit connected thereto, said data terminal comprising: an input buffer and a receiving unit; first internal clock means, distinct from said central clocks, for generating a first pulse train at the frequency of the bit stream on the transmission line; second internal clock means, distinct from said central clocks, for generating a second pulse train at a substantially lower frequency than the first pulse train; means responsive to a selected channel pulse of the central channel clock for connecting the input buffer to the transmission line and for transferring into the input buffer the bit stream carried by the transmission line for the duration of said selected channel pulse, said transfer taking place at the frequency of said first clock pulse train; means for transferring the contents of the input buffer to the receiving unit at the frequency of said second clock pulse train; and means for synchronizing the first and second internal clock means with the bit rate of the bit stream on the transmission line.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |