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User Guide
40
• Time references. Includes the ToD reference. The ToD is made up of a 1 PPS that
provides accurate phase timing and a protocol that distributes the time in an abso-
lute time scale such as TAI or UTC. The ToD can be used to measure TE in any
interface including, PTP, 1 PPS and frequency.
• Phase references. They are the 1 PPS and the 1 PP2S references. Phase refer-
ences offer something that is in between time and frequency references. They can
be used to measure TE in other phase references such as 1 PPS and 1 PP2S but
they cannot do the measurement with time protocols such as IEEE 1588 / PTP.
GNSS has not been included in the previous description but from the point of view of
the functionality it offers is equivalent to a ToD reference. There are some points
specific about GNSS references: Timing is generated from one or various satellite
constellations and information about geographical position and not only time is
received. For this, GNSS references are configured separately (See section 2.6.2).
Table 2.12: Clock/PCM input and output interfaces
Parameter Description
Clock/PCM input Configures the Clock or PCM reference input interface:
• 2048 kHz (Port Ref. In/Out): The clock reference is derived
from an external ITU-T G.703 2048 kHz signal. This signal
is received through the balanced RJ-48 Ref. In / Out port.
• E1 (Port Ref. In/Out): The clock reference is derived from
an external ITU-T G.703 2048 kb/s signal. This signal is
received through the balanced RJ-48 Ref. In / Out port.
• 1544 kHz (Port Ref. In/Out): The clock reference is derived
from an external 1544 kHz signal. This signal is received
through the balanced RJ-48 Ref. In / Out port.
• T1 (Port Ref. In/Out): The clock reference is derived from
an external ITU-T G.703 1544 kb/s signal. This signal is
received through the balanced RJ-48 Ref. In / Out port.
• 5 MHz (Port Ref. In/Out): This is a 5 MHz unipolar clock.
Accepts square or sinusoidal signal received through the
RJ-48 Ref. In / Out port.
• 10 MHz (Port Ref. In/Out): This is a 10 MHz unipolar clock
input. Accepts square or sinusoidal signal received
through the RJ-48 Ref. In / Out port.
Connector Configures the port connector in a Clock / PCM reference
input. Since all references of this type are currently received
through the balanced RJ-48 Ref. In / Out port, connector set-
ting is not required.
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