Comtech EF Data SDM-650B - Manual (Page 50)

Configuration SDM-650B Satellite Modem
3–8 Rev. 5
Electrical characteristics of the RS-422 interface signals are defined in EIA-STD-RS-422.
Electrical characteristics of the MIL-STD-188-114 interface signals are defined in
MIL-STD-188-114 and MIL-STD-188-100.
• EIA-STD-RS-449 provides details of the mechanical interface.
• MIL-STD-188-114 defines signal levels, offsets, termination resistors, etc.
• MIL-STD-188-100 specifies such characteristics as signal quality and clock/data
phase relationships.
INT/EXT CLOCK
TO CONTROL LOGIC
LOOP TIMING
TO LOGIC CONTROL TO BUFFER
OPTIONS
SCT
M
O
D
E
M
TX CLOCK
TX DATA
AUTO
CLOCK
SELECT
TO CONTROL LOGIC
LOOPBACK
T
E
R
R
E
S
T
R
I
A
L
TT
RT
SD
RD
ST
MC EXTERNAL BUFFER CLOCK
INVERT
NORM
TO BUFFER
OPTIONS
RX CLOCK
RX DATA
COMMON EQUIPMENT
MODULATOR
DEMODULATOR
FAULT
RELAYS
CONTROL
LOGIC
RTS TO CTS JUMPER
TTL MODULATOR FAULT
SPARE (RS-232 ONLY)
RS
CS
TTL DEMODULATOR FAULT DATA BUS TO M & C
JP1
JP2
JP8
JP3
JP9
JP12
Figure 3-3. RS-422 and MIL-STD-188-114 Block Diagram