This article explains how to bring qfx5120 console connection.

Before you connect and configure a QFX5120, set the following parameter values on the console server or desktop PC:

• Baud Rate—9600
• Data—8
• Flow Control—None
• Parity—None
• Stop Bits—1
• DCD State—Disregard

Ensure that you have the following parts and tools available:

• An Ethernet cable with an RJ-45 connector attached—not provided
• An RJ-45 to DB-9 serial port adapter—not provided
• A management host such as a laptop or desktop PC, with a serial port—not provided

This article explains how to bring qfx5120 console connection.

Before you connect and configure a QFX5120, set the following parameter values on the console server or desktop PC:

• Baud Rate—9600
• Data—8
• Flow Control—None
• Parity—None
• Stop Bits—1
• DCD State—Disregard

Ensure that you have the following parts and tools available:

• An Ethernet cable with an RJ-45 connector attached—not provided
• An RJ-45 to DB-9 serial port adapter—not provided
• A management host such as a laptop or desktop PC, with a serial port—not provided

You can use below doc for more details.

https://www.juniper.net/documentation/us/en/hardware/qfx5120/topics/topic-map/qfx5120-configure-junos-os.html