T1/E1 Frame Generator With Ssm Switch Block S3 - Symmetricom TSG-3800 Series User Manual

CPU, Frame Generator, and Clock Modules
T1/E1 Frame Generator Module with SSM
The setting of Rocker 2 determines the type of framing used by the E1 frame
generator.
On Rocker 3, the OFF position selects HDB3 encoding. The ON position selects
AMI encoding.
The setting of Rocker 5 determines the multiframe format generated by the T1
frame generator. In the OFF position the ESF format is enabled. In the ON position,
Rocker 5 enables D4 framing. Set this according to the equipment using the framed,
all ones output of the output modules.
SSM is controlled by Rocker 6. When this function is enabled (Rocker 6 OFF), the
CPU sends a status message to the frame generator, which transmits it through the
Facility Data Link of the ESF signal (Rocker 5 OFF). If the CPU module is removed
from the TSG, the frame generator begins sending the SSM, "00001000", which
indicates "Sync Quality Unknown" in the DS1 ESF signal. SSM is disabled when
Rocker 6 is ON. This causes all of the message bits on the Facility Data Link to be
sent as ONEs.
Setting Switch Block S3
This switch is only present on the 23478443-xxx-0 modules; E1 SSMs are not
available on the 23478305-xxx-0 modules. S3 is located in the upper right corner of
the module (see
3, which are used to set the bit position in time slot zero of the not frame alignment
word of an E1 signal, where the SSM will be inserted. By setting these switches to a
specific combination of OFFs and ONs, the SSM will be inserted into the desired bit
position in the bit stream. The following table shows the settings of the three rocker
switches for each of the five allowed bit positions. Be careful to set the S3 rockers
on both Frame Generators in the TSG-3800 to the same positions. If this is not
done, the SSM will change bit position when the selected Frame Generator is
changed from A to B, or B to A.
The SSM inserted into the bit stream is written to a register on the Frame Generator
module by the CPU module. The SSM can be automatically determined and
inserted, or it can be manually set. For a description of the SSM function, refer to
the FG command in
Table 6-17. T1/E1 Frame Generator with SSM Switch Block S3
Rocker
1
2
3
192 TSG-3800 User's Guide
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Figure 6-8). S3 consists of three rocker switches labeled 1, 2 and
Appendix , Software
Bit 4 Bit 5
OFF ON OFF
OFF ON ON
ON OFF OFF
Commands.
Bit 6 Bit 7 Bit 8
ON OFF
OFF OFF
OFF OFF
12778474-002-2 Revision F – March 2004