CDM-625 Advanced Satellite Modem
Revision 1
Clock Modes and Drop and Insert (D&I)
MN-0000036 (Ref MN/CDM625.IOM)
detects no activity at IDI input, or cannot detect the expected frame format, Buffer Clock = Rx
Satellite will be chosen as a fall-back.
If ‘Insert’ is
not
the selected buffer clock reference, the clock and data from the IDI port is
ignored, and a new E1/T1 frame is generated. The time slots coming from the satellite are then re-
inserted into the selected timeslots of this new blank frame, and output on the IDO port.
9.10 Single-Source Multiple Modems
Two ways to connect a single T1 or E1 stream to several modems are by looming or daisy-chaining
modems. Looming method is illustrated in
Figure 10-5,
and
Figure 10-6
illustrates the daisy-chain
method; each requires the RX Buffer Clock = Insert setting.
•
Assign all timeslots to not overlap.
•
Assign modems to number of TX/RX channels as required.
Figure 9-5. Single-Source Multiple Modems (Looming)
DDI
DDO
IDI
IDO
MODEM
MODEM
MODEM
Terrestrial Trunk
Multiple Modem Drop & Insert Application: This application shows how the loop is extended
to one or more additional modems.
DDO- IDI connection may be made internally using Loop = Y under D&I menu.
IDI
Figure 9-6. Single-Source Multiple Modems (Daisy-chain)
9–9
