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SDM-300A Satellite Modem
Channel # 1 Satellite Data Rates
Channel # 1 Terrestrial Framing
Channel # 1 Satellite Overhead
Channel # 1 Timeslot Selection
User Channel # 2 ADPCM Audio Channel
Channel # 3 and # 4 Data Interface
(Synchronous Mode)
Channel # 3 and # 4 Clock Output (Synchronous
mode)
Channel # 3 and # 4 Data Interface
(Asynchronous mode)
Rev. 4
Table A-24. Multiplexer Specification
Multiplexer Specific Specifications
E1 Data Rates
N = 1 through 6, 8, 10, 12, 15, 16, 20, 24 or 30 (E1_CCS)
N = 1, 2, 3, 4, 6, 8, 12, 16, 24, 30 (E1_CAS)
E1 (2048 kbit/s)
T1 Data Rates
N = 1 through 6, 8, 10, 12, 15, 16, 20 or 24 (T1)
(add 9 or 18 for T1, using special IBS superframe)
T1 (1544 kbit/s)
G.732, G.733 and G.704
16/15 of data rate per IESS-308, Rev. 6 and IESS-309, Rev. 3.
Applies when only Channel # 1 is selected, all other channels are "disabled".
1 to 24 (All T1 modes)
1 to 15, 17 to 31 (E1_CAS and E1_CCS)
1 to 31 (E1_31TS)(Slot 16 available)
Arbitrary order, non-contiguous available.
32 kbit/s audio channel 600Ω, balanced 4-wire.
The multiplexer supports synchronous data from each tributary. The tributary
interface use DCE conventions with data (Send data) sourced by external
equipment and clock (Send timing) sourced by the multiplexer.
50% duty cycle ± 10%, clock (Send timing) is phase locked to aggregate clock
supplied by the modem or an external reference supplied by the user equipment.
Clock stability is based on the reference equipment.
The multiplexer supports asynchronous data interface for each tributary data
interface. The data interface uses (DCE) conventions with data (Send data)
sourced by external equipment. The multiplexer samples data and passes it
across the communications channel. All data formatting and framing is
preserved.
Note: CTS (Clear-to-Send) flow control is employed to prevent loss of data
caused by clock differences between the asynchronous source and the
asynchronous satellite channel.
Options
A–81
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