Connecting the EX9253 to External Devices
Connect a Device to a Network for Out-of-Band Management
Ensure that you have an Ethernet cable that has an RJ-45 connector at either end. Figure 1 shows the RJ-45 connector of the Ethernet cable supplied with the device.

You can monitor and manage these devices by using a dedicated management channel. Each device has a management port to which you can connect an Ethernet cable with an RJ-45 connector. Use the management port to connect the device to the management device.
To connect a device to a network for out-of-band management (see Figure 2):
- Connect one end of the Ethernet cable to the management port on the device.
- Connect the other end of the Ethernet cable to the management device.

Connect a Device to a Management Console Using an RJ-45 Connector
Ensure that you have an Ethernet cable that has an RJ-45 connector at either end. One such cable and an RJ-45 to DB-9 serial port adapter are supplied with the device.
Figure 3 shows the RJ-45 connector of the Ethernet cable.

If your laptop or desktop PC does not have a DB-9 plug connector pin and you want to connect your laptop or desktop PC directly to the device, use a combination of the RJ-45 to DB-9 socket adapter supplied with the device and a USB to DB-9 plug adapter. You must provide the USB to DB-9 plug adapter.
You can configure and manage devices using a dedicated management channel. Each device has a console port which you can connect to using an Ethernet cable with an RJ-45 connector. Use the console port to connect the device to the console server or management console. The console port accepts a cable that has an RJ-45 connector.
To connect the device to a management console (see Figure 4 and Figure 5):
- Connect one end of the Ethernet cable to the console port (labeled CON, CONSOLE, or CON1) on the device.
- Connect the other end of the Ethernet cable to the console server (see Figure 4) or management console (see Figure 5).


Connecting the EX9253 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 6 shows the ports that are 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
- Connecting a BITS External Clocking Device to the Switch
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 6).
Ensure that a cable of 3 m or less in length is used for the 10-MHz and 1-PPS connectors.
To connect the SMB coaxial cable to the external clocking input port:
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 6).
To connect the switch to a BITS external clocking device:
- 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.
- Plug one end of an RJ-45 cable into the internal clock port on the front panel.
- Plug the other end of the RJ-45 cable into the BITS external clocking device.
- Verify that the LEDs for the BITS port are lit steadily green.
- Configure the port.
Configuring Clock Synchronization Interface on EX9251 and EX9253 Switches
Starting with Junos OS Release 18.1R1, EX9251 switches support external clock synchronization for Synchronous Ethernet, T1 or E1 line timing sources, and external inputs. Starting with Junos OS Release 18.2R1, EX9253 switches support external clock synchronization for Synchronous Ethernet, T1 or E1 line timing sources, and external inputs. Configuring external clock synchronization requires making clock selection, quality level, and priority considerations. The clock source selection algorithm is used to pick the two best upstream clock sources from among the various sources on the basis of system configuration and execution criteria such as quality level, priority, and hardware restrictions.
Configuring Clock Synchronization Options
To configure the clock synchronization options.