Comtech EF Data SDM-300A - Manual (Page 324)

SDM-300A Sattellite Modem Revision 6
Flex Mux MN/SDM300A.IOM
15–4
Table 15-2. Multiplexer Specification
Multiplexer Specific Specifications
Channel # 1 Satellite Data Rates 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 kbps)
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 kbps)
Channel # 1 Terrestrial Framing G.732, G.733 and G.704
Channel # 1 Satellite Overhead 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”.
Channel # 1 Timeslot Selection 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.
User Channel # 2 ADPCM Audio Channel 32 kbps audio channel 600 Ω, balanced 4-wire.
Channel # 3 and # 4 Data Interface
(Synchronous Mode) 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.
Channel # 3 and # 4 Clock Output (Synchronous
mode)
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.
Channel # 3 and # 4 Data Interface
(Asynchronous mode)
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.