Time Slot Selection - Comtech EF Data CDM-600 Operating Instructions Manual

CDM-600 Satellite Modem
Clock Modes and Drop and Insert (D&I)
10.6

Time Slot Selection

Selection of the transmit and receive data rates may be made in certain 64 kbps
increments and may be independent of each other. The actual satellite rates for open
network D&I are 16/15 of the transmit or receive data rate to include IBS overhead per
IESS 309, although this is transparent to the user. For E1, the user can select any time
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slot (TS) from 1 to 31. Selection of TS 0 is not permitted. For T1, the user can select any
time slot (TS) from 1 to 24. The user may also select "N/A" to leave a satellite channel
unused.
The configuration menu allows time slots to be selected for transmission or reception up
to the maximum dictated by the selected transmit or receive data rate, and may be
selected in arbitrary order. As an example, if the data rate is set to 256 kbps, the
maximum number of time slots that can be dropped or inserted is 4 (being 4 x 64 kbps).
Note that for 1920 kbps data rate the timeslots may not be manipulated. This is the 'fixed
channel' mode where Timeslot 1 is assigned to Channel 1, and so on.
For D&I++ framing, all increments of 64 kbps are allowed up to a maximum of 24 (1536
kbps). For this mode, the satellite rate is 46/45 of the front panel data rate (2.22%).
10–8
Revision 7
MN/CDM600.IOM