Cisco 2600 Series Operation Manual page 135

Figure 13-4
HIGH SPEED SERIAL
1HSSI
All network modules have an enable (EN) LED. The enable LED indicates that the module
has passed its self-tests and is available to the router. The HSSI network module has the
additional LEDs shown in Table 13-1.
Table 13-1 HSSI Network Module LEDs
LED
LB/C (Loopback/Connect)
RC (Receive Clock)
RD (Receive Data)
TC (Transmit Clock)
TD (Transmit Data)
1 DSU = data service unit.
2 DTE = data terminal equipment.
3 DCE = data communications equipment.
HSSI Network Module LEDs
Meaning
Green indicates normal operation. The module is connected to the external DSU
2
the signals TA (DTE available) and CA (DCE
Yellow indicates that the module is in loopback mode.
If this LED is off, the port is neither connected to the DSU nor in loopback mode.
Module has detected a receive clock signal. During normal operation, this signal is
received from the external DSU. During loopback, it is generated internally.
Module has detected a receive clock signal. During normal operation, this signal is
received from the external DSU. During loopback, it is generated internally.
Module is transmitting a clock signal to the external DSU. During normal operation,
this signal is derived from the DSU's RT signal. During loopback, it is generated
internally.
Module has been detected by and can send packets to the external DSU.
HSSI port LEDs
3
available) are active.
Connecting HSSI Network Modules to a Network 13-5
HSSI Network Module LEDs
HSSI 0
EN
Enable LED
1
, and