AT&T Release 2.0 manual Signal Monitor Unit Front-Panel LEDs Label Color, Provides

Connecting the Control Unit to the Network Interface

Table 4-24. Signal Monitor Unit Front-Panel LEDs

Label Color

Avg. Dens Red

Zeroes Red

When Lit Indicates

Low average ones density

>50 consecutive zeroes (needed for encryption) or > 16 consecutive zeroes (option switch S4 closed)

Line Pwr	Yellow	Presence of simplex current
Looped	Yellow	Loopback function activated
BPV	Red	Bipolar violations received
Pulse	Green	Normal 1.544-Mbps pulses present

Table 4-25. Signal Monitor Unit Front-Panel Test Jacks

J a c k

EQ (IN-OUT-MON)

SM (lN-OUT-MON)

Provides

Access to transmit input and receive output of the 100D module

Access to CSU transmit input and receive output

Installing the Channel Service Unit 4-39