Comtech EF Data SDM-650B - Manual (Page 74)

Configuration SDM-650B Satellite Modem
3–32 Rev. 5
RECEIVE SECTION TRANSMIT SECTION
INTERFACE
ES TO ES ASYNC
LOGIC (MUX)
RS-232 TIMING
FRAMING/
P/O
INT
LPBK
MODEM
P/O
INT
LPBK
RS-232
INTERFACE
ES TO ES
ASYNC
DEFRAME/TIMING
LOGIC (DEMUX)
TX DEJITTER
T1/E1 INTERFACE
G.703
T2/E2
P/O
BASE
BAND
PLESIOCHRONOUS
BUFFER
P/O
BASE
BAND
LPBK
T1/E1
T2/E2
INTERFACE
RS-422
G.703
CLK
CLK
DATA
V.35
INTERFACE
INTERFACE
MIL-STD
188-114
LPBK
RS-422 INTERFACE CLK
DATA
MIL-STD-188-114
V.35 INTERFACE
CLK
DATA
INTERNAL CLOCK
SATELLITE CLOCK
CLOCK SYNTHESIS
DATA
EXTERNAL REFERENCE CLOCK
TRANSMIT TERR CLOCK
CLOCK
SYNTHESIS
EXTERNAL REFERENCE CLOCK
INTERNAL CLOCK
(TRANSMIT TERR CLOCK)
Figure 3-12. Asynchronous Overhead Interface Block Diagram
3.2.5.2 Terrestrial Interface
The terrestrial interface, AS/1311, forms the top (when mated with the connector board)
of the 2-board module. The interface contains all balanced pair drivers and receivers for
RS-422, MIL-STD-188, and V.35.
Data inputs are SD and transmit clock (TT or SCTE).
Data outputs are:
• Modem reference clock (SCT or ST)
• Receive data (RD)
• Receive clock (RT or SCR)