Connecting the Switch to External Clocking and Timing Devices

The switch supports external clock synchronization for Synchronous Ethernet and external inputs. The connections to the switch are made through the ports on the front panel. Figure 10 shows the ports that are used to connect the switch to external clocking and timing devices.

Figure 10: Ports Used to Connect the Switch to External Clocking and Timing Devices

1 — Time-of-day (ToD) port with LED. Support for this port is not available in this release.	3 — 10-MHz input and output timing ports
2 — BITS ports with LEDs	4 — 1-PPS input and output timing ports

Connecting 1-PPS and 10-MHz Timing Devices to the Switch

The switch has four SubMiniature B (SMB) connectors that support 1-PPS and 10-MHz timing devices (see Figure 10).

1. Connect one end of the SMB coaxial cable to either the socket labeled IN on the 1-PPS SMB connector or the 10-MHz SMB connector on the switch.
2. Connect the other end of the SMB coaxial cable to the 1-PPS or 10-MHz source network equipment.Note

   Ensure that the 1-PPS or 10-MHz source network equipment contains low voltage complementary metal oxide semiconductor (LVCMOS) or is compatible with low-voltage (3.3 V) transistor–transistor logic (LVTTL).

Connecting a BITS External Clocking Device to the Switch

The switch has an external building-integrated timing supply (BITS) port, labeled BITS, on the front panel of the switch (see Figure 10).

1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
2. Plug one end of an RJ-45 cable into the internal clock port on the front panel.
3. Plug the other end of the RJ-45 cable into the BITS external clocking device.
4. Verify that the LEDs for the BITS port are lit steadily green.
5. Configure the port.