Comtech EF Data SDM-2020 - Manual (Page 126)

SDM-2020 Satellite Modulator Revision 7
ECL/HSSI TX MN/SDM2020M.IOM
10-5
0 1 0 0 1 0 1 1
8 Bits Sync 1496 Bits Payload
SYNC
DATA
DVALID
CLOCK
0 1 0 0 1 0 1 1
8 Bits Sync 128 Bits RS
Figure 10-4. 204 Byte DBS Serial Format
10.1.4.2 T
ERRESTRIAL
S
IGNAL
D
EFINITION
HSSI (High Speed Serial Interface per Cisco Systems, Inc.) and EIA-613 (High Speed
Serial Interface for Data Terminal Equipment and Data Circuit-Terminating Equipment)
specifications define the high-speed serial port functionality. The serial port is referred to
as the HSSI Interface. The HSSI Interface is compatible with EIA-613/EIA-612.
Additional non-standard signals will be included on reserved pins and are highlighted in
the signal definition table.
Note: Standard EIA-613 defines the interconnection of data terminal equipment (DTE)
and data circuit-termination equipment (DCE) utilizing high speed serial circuits. The
SDM-2020 modulator/demodulator is defined as a DCE.
Refer to Table 10-3 for HSSI pinouts and Figure 10-5 for pinout locations.
Figure 10-6 shows the HSSI signal flow and naming convention for defined signals.
Table 10-3. HSSI/EIA-613 Interface Connector Pinout (J3)
Signal Function HSSI
Signal
EIA-613
Circuit
Pin # (+, -) Circuit
Direction
Comment
Signal Ground SG 102 1, 26 Mod/Demod
Receive Timing RT 115 2, 27 from DCE Demodulator
DCE Available CA 107 3, 28 from DCE Mod/Demod
Receive Data RD 104 4, 29 from DCE Demodulator
Loopback Circuit C LC undefined 5, 30 from DCE Mod/Demod
Send Timing ST 114 6, 31 from DCE Modulator
Signal Ground SG 102 7, 32 Mod/Demod
DTE Available TA 108/2 8, 33 to DCE Mod/Demod
Terminal Timing TT 113 9, 34 to DCE Modulator
Loopback Circuit A LA 143 10, 35 to DCE Mod/Demod
Send Data SD 103 11, 36 to DCE Modulator