CHAPTER 6: Testing and Diagnostics
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6. Testing and Diagnostics
This chapter includes a description of the mux’s diagnostic tests and troubleshooting procedures.
6.1 Diagnostic Tests
The mux supports three types of loopback connections:
• local loopbacks in the local mux unit,
• local loopbacks in the remote mux unit, and
• remote loopbacks in the remote T1 or E1 (depending on the version you have).
6.1.1 L
OCAL
L
OOPBACKS IN THE
L
OCAL
M
UX
You can set two types of local loopback connections in the local mux unit:
• T1 or E1 local, which is set for each T1 or E1 interface separately from a terminal.
• Fiber optic link local, which can be set from a terminal.
T1 or E1 local loopback in the local mux
The T1 or E1 local loopback returns the T1 or E1 transmit signal to the output of the receive path
(Figure 6-1). This test checks the operation of the connections to the equipment attached to the local channel
interfaces.
Fiber optic link local loopback in local mux
The fiber optic local loopback returns the transmit signal of the active fiber optic link interface to the input of
the receive path. Simultaneously, the local T1 or E1 Fiber Mux sends an unframed all-ones signal to the fiber
optic link. Figure 6-2 shows the fiber optic link local loopback connection.
When this loopback is activated, the equipment connected to the local mux channel must receive its own
transmission. The LOC TEST indicator lights while the loopback is activated. This test checks the operation of
the local mux and the connections to the equipment attached to the channel interfaces.