Premier Mounts CDM-600 Rx Buffer Clock = Insert D&I only, Single-Source Multiple Modems

CDM-600 Satellite Modem	Revision 7
Clock Modes and Drop and Insert (D&I)	MN/CDM600.IOM

10.8Rx Buffer Clock = Insert (D&I only)

The E1 or T1 clock recovery from the IDI G.703 port serves as the Rx Buffer reference. In addition, the recovered data is the E1/T1 input to the Insert Mux. If the Rx G.703 recovery circuit 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.

10.9Single-Source Multiple Modems

Two ways to connect a single T1 or E1 stream to several modems are by looming or daisy-chaining modems. Each method is illustrated in Figure 10-5 for Looming and Figure 10-6 for daisy chain and each requires the RX Buffer Clock = Insert setting.

•Assign all timeslots to not overlap.

•Assign modems to number of TX/RX channels as required.

DDI(TX)

DDO(LOOP)

IDI(LOOP)

IDO(RX)

DDI(TX)

DDO(LOOP)

IDI(LOOP)

IDO(RX)

DDI(TX)

DDO(LOOP)

IDI(LOOP)

IDO(RX)

BIT ERROR TEST

-- - - - - - - - - Receive

___________ Transmit

Figure 10-5. Single-Source Multiple Modems (Looming)

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