SN55107A, SN75107A, SN75107B, SN75108A

DUAL LINE RECEIVERS

SLLS069D – JANUARY 1977 – REVISED APRIL 1998

14

POST OFFICE BOX 655303

Two methods of terminating a transmission line to reduce reflections are shown in Figure 16. The first method

uses the resistors as the attenuation network and line termination. The second method uses two additional

resistors for the line terminations.

APPLICATION INFORMATION

R3

R3

R3

R1

(see Note A)

R2

(see Note A)

R2

R1

R3 = R1 + R2 = ZO /2

Method 2

R2

R1

R3

R1 + R2 > ZO

R3 = ZO /2

R2

(see Note A)

R3

R3

R1

Method 1

NOTE A: To minimize the loading, the values of R1 and R2 should be fairly large. Examples of possible values are shown in Table 1.

Figure 16. Termination Techniques

For party-line operation, method 2 should be used as shown in Figure 17.

Attenuation Network

R3

+

Z

O

2

R3

+

Z

O

2

R3

+

Z

O

2

R3

+

Z

O

2

Figure 17. Party-Line Termination Technique