Title: Test system for a T carrier type telephone PCM communications system

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Claims: What is claimed is:

1. In a pulse code modulation (PCM) type communications system having repeater stations the PCM signal normally being in bipolar format and where such repeater stations may be tested by a plurality of test signals having relatively low frequencies compared to the PCM rate, such test signals being formed by trio sets which consist of a PCM pulse of one polarity between two pulses of the opposite polarity said pulses occupying three contiguous time slots of said PCM system, a plurality of trio sets of one type forming a trio group, sequential trio groups of opposite types providing a base line shift in the test signal which varies in polarity at a selected one of said low frequencies; said system including means for converting said trio sets to quadruple sets which have four pulses occupying four contiguous time slots for providing a signal which is sequentially bipolar with no dc offset.

2. A communications system as in claim 1 where said converting means includes trio set detecting means, stuffing means responsive to the detection of a trio set by said detecting means for stuffing a fourth pulse to provide said quadruple sets, and delete means for deleting said fourth pulse in response to an ambiguity in a trio set.

3. A communications system as in claim 1 including reconverter means responsive to an external command for reconverting said quadruple sets to trio sets.

4. A communications system as in claim 3 where said reconverter means is connected between an outgoing and incoming line from a central office to thereby provide a remote loopback.

5. A communications system as in claim 1 where said converting means includes trio set detecting means and stuffing means responsive to the detection of a trio set by said detecting means for stuffing a fourth pulse to provide said quadruple sets.

Other info:

Inventors: Dotter, Jr., Berton E. (Belmont, CA, US)

Application Number: 540813
Filing Date: 1975-01-14
Publication_date: 1976-06-22
Assignee: TRW Inc. (Los Angeles, CA)
Primary Class(es): 375/211 375/213, 375/242, 375/289
Other Classes:
US Patent Ref:

3649777	Mar, 1972	Matsushima	179/175.
3739098	Jun, 1973	Camiciottoli et al.	179/175.
3764760	Oct, 1973	Marchini	179/175.
3770913	Nov, 1973	Camiciottoli et al.	179/175.
3842220	Oct, 1974	Arras	179/175.

Other Refs:
Primary Examiner: Olms, Douglas W.
Assistant Examiner:
Attorney: Flehr, Hohbach, Test, Albritton & Herbert