Comtech EF Data CDM-425, Installation And Operation Manual

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CDM-425 Advanced Satellite Modem
Revision 0
Appendix E E–9 MN-CDM-425
E.8 Drop and Insert (D&I) Clocking
Figure E-4 shows the general arrangement for D&I clocking in the CDM-425 Advanced Satellite
Modem. There are two inputs and two outputs shown for D&I Operation:
•
Drop Data In (DDI)
•
Drop Data Out (DDO)
•
Insert Data In (IDI)
•
Insert Data Out (IDO)
This arrangement permits you to choose between fully independent operation of the incoming and
outgoing E1/T1 signal, or to use the same T1/E1 signal for both Dropping and Inserting (looped
mode). If ‘Loop’ has been selected under the D&I configuration menu, the DDO signal is
automatically looped internally, to become the IDI.
In this mode, timeslots are dropped from an incoming E1/T1 signal for transmission over the
satellite, and the
same E1/T1 signal has timeslots re-inserted into it that will over-write data in
existing timeslots.
Figure E-4. Drop and Insert Clocking