Title: Two-wire resistance bridges for private line circuits

We claim as our invention:

1. A 2-wire multileg resistance branching network for interconnecting a plurality of voiceband telecommunication lines in a system having standardized input and output line levels, said network comprising

electrical conductor means forming a pair of common junctions,

at least three substantially identical 2-conductor signal transmission legs, each including a pair of input-output terminals and a pair of resistors, one resistor in each leg being connected between one terminal of that leg and one of said junctions, the other resistor in each leg being connected between the other terminal of that leg and the other of said junctions, and

a shunt resistance connected between said junctions,

said leg resistors all being of substantially the same value,

said shunt resistance having a value selected to provide a network attenuation ratio substantially equal to the difference in said standardized levels.

2. The network of claim 1, wherein said shunt resistance is selected to provide an attenuation ratio of about 22.6 dB.

3. The network of claim 1, wherein said leg resistors have a value of about 260 ohms.


Other info:


Inventors: Dannenmann Jr., John E. (Portland, OR)
Johnson, Bill E. (Portland, OR)

Application Number: 06/120840
Filing Date: 1980-02-12
Publication_date: 1981-08-25
Assignee: BEJED INC

Primary Class(es): 379/206.010 333/130, 379/398
Other Classes: H04B1/58; H04M3/56; H04B1/54; H04M3/56; H04B1/58
US Patent Ref:

4140875

February, 1979

Johnson et al.

179/1CN

Four-wire, eight-leg bridge

Other Refs: GB1353367

May, 1974

179/1CN

Primary Examiner: Popek, Joseph A.
Assistant Examiner:
Attorney: Mufatti, William F.