Laser Lockout, Remote Interlock; Sync Output; Bits Ext Ref - Tektronix ST2400A User Manual

Laser Lockout, Remote Interlock

LASER LOCKOUT is a safety device. The key switch disables the Transmitter's 2.4 Gb/s laser
output when it is turned to the 0 (zero) position. The laser output can only be turned on when the
key is in the 1 (one) position.
REMOTE INTERLOCK is a bantam plug normally closed connection internally wired in series with
the laser lockout key switch. It can be used with additional hardware to disable the Transmitter 2.4
Gb/s laser output.
NOTE: The Transmitter 2.4 Gb/s Laser output cannot be enabled unless:
•
The Laser Lockout key switch is set to the on (1) position.
•
The Remote Interlock, which is normally enabled, is either not used or externally enabled.
•
The Laser output is software enabled.
W A R N I N G ! W A R N I N G !
Before activating the 2.4 Gb/s LASER, its output must be connected to a circuit.
C A U T I O N ! C A U T I O N !
Always use 15 dB of attenuation when connecting the ST2400A Transmitter output to its
Receiver input. Failure to do so will damage the optical detector.
SYNC Output (SMA)
SYNC Output (Clock Trigger) is an AC-coupled output. The voltage level is
300 mV peak-to-peak minimum. This output requires an external 50-Ohm termination to work
properly. This output generates a sync output signal at 1/8 data rate (311 Mhz), useful for
triggering a oscilloscope to measure the eye diagram of an OC-48/STM-16 signal.

BITS Ext Ref

In addition to the external 2.048 Mb/s or 2 MHz SETS timing input on the front panel, the
ST2400A accepts 1.544 Mb/s ± 40 PPM BITS input for internal signal generation using external
timing synchronization. BITS input accepts signals meeting the requirements of ANSI T1.101-
1994 with the exception of frequency tolerance of +/- 40 PPM.
BITS external timing input is a Bantam connector mounted on ST2400A rear panel. The Rear
panel connector is labeled BITS Ext Ref, to indicate its input timing function.
The user has the ability to select which of the timing sources (internal, ext 1.544 Mb/s, or ext
2.048 Mb/s/MHz) is active. When an external clock source is detected, but no clock activity is
detected, the user is alerted to Loss of External Clock, via a front panel message.
ST2400A SDH Test Set User Manual
Functional Overview
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