Verilink C100 (880-502893-001) Product Manual - Manual (Page 48)

LED Indicators and Diagnostics
4-8 Verilink C100 and C150 T1/FT1 CSU/DSU 6/15/99
Local Payload
Loopback C100 and C150
The C150 Local Payload LOOPBACK LED is on solid when it is
selected by the Select push-button. When the Local Payload
LOOPBACK LED blinks at a fast rate, the T-1 CSU/DSU is in a
Payload Loopback and was activated locally. (See circled loops in the
illustrations below.)
When the Local Payload Loopback LED blinks at a slow rate the T-1
CSU/DSU is in a Payload loopback activated by the T1 carrie
provider or the remote end.
This loopback can be used when in both D4 and ESF Framing.
The color of this LED is red.
Figure 4-9 C100T-1 CSU/DSU in Local Payload Loopback
Figure 4-10 C150 T-1 CSU/DSU in Local Payload Loopback
Remote Network
Interface (NI)
Loopback The Remote Network Interface (NI) LOOPBACK LED is on solid whe
it is selected by the Select push-button. When the Remote NI
LOOPBACK LED blinks at a fast rate, the T-1 CSU/DSU has sent a
LOOP UP (Remote NI loop) command to the T-1 CSU/DSU (see
circled loop i
Figure 4-11 for the C100) at the other end of the
Network. Since this loopback latches the unit at the other end, care
Pattern
Checker
Pattern
Generator
T-1 CSU Channel
Remote T-1 CSU/DSU
Pattern
Checker
Pattern
Generator
T-1 CSU Channel
Local T-1 CSU/DSU
Bridge Bridge
NI NI
NETWORK Router Router
Bridge
Pattern
Checker
Pattern
Generator
T-1 CSU DSX1
Channel
Remote T-1 CSU/DSU
Pattern
Checker
Pattern
Generator
T-1 CSU DSX1
Channel
Local T-1 CSU/DSU
PB PB
Bridge
NI NI
NETWORK
Router Router