Comtech EF Data CDM-625 - Manual (Page 323)

CDM-625 Advanced Satellite Modem Revision 15
Clock Modes and Drop and Insert (D&I) MN-CDM625
9–9
9.8 Drop and Insert (D&I) Clocking
Figure 9-4 shows the general arrangement for Drop and Insert clocking in the CDM-625. Note
that there are two inputs and two outputs shown for Drop and Insert 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 Drop and Insert configuration menu, the
Drop Data Out (DDO) signal is automatically looped internally, to become the Insert Data In (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 9-4. Drop and Insert Clocking