B.3 Functional Descriptions - Comtech EF Data CDM-710 Installation And Operation Manual

CDM-710/L Broadcast Satellite Modem
Appendix B
B.3 Functional Descriptions
• Chapter 7. FRONT PANEL OPERATION
• Chapter 8. ETHERNET INTERFACE OPERATION
• Chapter 9. SERIAL NTERFACE OPERATION
Operation for either ASI module is selected by programming the module for
operation either from the CDM-710/L front panel keypad and VFD, or from the
HTTP (Web Server) or serial remote interfaces.
B.3.1 Input/Output Data Formats
The CDI-40 operates at a 270 Mbps transport rate for all data rates. The required
encoding of this transport is defined in EN 80053-9 and the Cypress Hotlink IC
data sheets. The information that follows applies to baseband data, not the data
transformed to the 270 Mbps physical transport layer.
There are two general modes of operation (note that the Tx interface correlates
from sync word or sync signal):
ASI Sync Mode
188 Mode
204 Mode
For ASI operation, data is either constant packet arrival or constant burst arrival
at the equivalent serial data rate. The standard frame formats / MPEG-2 I/O data
formats are as follows:
Data Format
Data
Transport Rate (ASI)
Description
The unit looks for a DVB/MPEG-2 frame consisting of 1 sync byte
(0x47) and 187 bytes of data. The frame structure is acquired by the
interface to create a satellite frame of 204 bytes by adding 16 bytes
of Reed-Solomon check bytes. The demodulator removes the 16
check bytes and the 188-byte frame is returned to the terrestrial
circuit.
The unit expects a DVB/MPEG-2 frame consisting of 1 sync byte
(0x47), 187 bytes of data and 16 bytes of filler.
Description
Payload data is byte serial with MSB first.
For 188 Mode, the payload is 187 bytes in length, preceded by a
sync word.
270 Mbps for all data rates.
B–5
MN/CDM710.IOM
Revision 12