# clock source

#### Syntax

clock source { line | internal { module | chassis } }

no clock source

#### Release Information

Command introduced before JunosE Release 7.1.0.

#### Description

Determines how an interfaces obtains clocking signals. The no version restores the default value, line.

#### Options

- line—Interface clocks data from a clock recovered from the line's receive data stream; the default.
- internal—Internal clock source transmits data from its internal clock. You must specify one of the following for internal clocking:
  - module—Internal clock is from the line module itself
  - chassis—Internal clock is from the configured system clock

#### Mode

Controller Configuration, Interface Configuration (POS only)