Using An External Frequency Reference (Ats-6511B Or C); Figure 4 External Frequency Reference - Symmetricom ATS-6511A User Manual

If these settings are correct ensure you use the save command to save the system settings
2.8

Using an External Frequency Reference (ATS-6511B or C)

Users may decide to provide an EXTERNAL frequency reference to the ATS-6511B or C. The
external frequency reference may be monitored by the ATS-6511B or C via a RS232 connection
through either of the USB Connectors on the rear of the unit (ATS 94001-5071A).
Symmetricom 5071A is currently the only model supported; users should contact Symmetricom
about the possibility of utilizing other clocks. The 5071A communications settings must be set to
9600 Baud, No Parity, 8 Data Bits, and 1 Stop Bit (9600,N,8,1) and a null modem serial cable
will be required.
WARNING: Prior to setting the reference to external ensure the 10MHz signal from the
reference is connected to the 10MHz IN connector on the rear of the ATS-6511B or C. If not, the
ATS-6511B or C outputs will not be within specification and it could take up to several hours for
the system to begin providing outputs within their specifications.
ATS-6511B -
Current status can be determined using the status reference:frequency:external command.
ATS-6511Bs >status reference:frequency:external
[communications] bad
[communications] n/a
[locked] true
[signal] missing
Note: Make sure the USB-to-Serial Converter (ATS 94001-5071A) is installed on one of the two
USB ports when the system is powered on. If not, power the system down, plug the cable in and
re-apply power. The USB/Serial Cables are programmed to communicate with an external
reference (ATS 94001-5071A) or to provide users access to the command port (ATS 94000-
115200). These cables are NOT interchangeable.
To set the type of reference use the reference_type command. If users are operating with a
Symmetricom 5071A and they will set the system up so the ATS-6511B is communicating with
the 5071A select hp5071A, if not select cesium.
ATS-6511B>reference_type hp5071a
[OK] 2013-08-13T18:05:30Z
10 MHz In
USB
To
USB
Serial

Figure 4 External Frequency Reference

10MHz reference signal is present but the system is unable to
communicate with the 5071A
10MHz reference signal is present. The system will not attempt to
communicate with the external reference.
10MHz reference signal is present and the system is able to
communicate with the 5071A
10MHz reference signal is not present. Do NOT select the reference
type as External.
20
ATS-6511A/B/C Users Guide
10 MHz
Port 1/2
RS-232
( DTE )
Null Modem
Cable
DOC 6511_Release K
The
5071
External reference