Comtech EF Data SDM-2020 - Manual (Page 145)

9–1
Chapter 9. ASI/RS422 INTERFACE
This section describes the plug-in ASI/RS422 Data Interface used with the SDM-2020
Demodulator.
9.1 ASI/RS-422 Interface (PL/5807)
This module contains both an ASI and an RS-422 interface. Only one of the interfaces
operates at a time as selected by the user. The ASI interface always operates at 270 Mbps
with the actual data rate imbedded within this rate.
• For ASI operation data bytes are converted to 10 bit words for transmission at
270 Mbps by the ASI integrated circuits. A reverse process recovers the data
bytes by other ASI integrated circuits.
• The second interface is compliant with EIA-530 and has a 25-pin female D
connector. This connector also has the modulator and demodulator open collector
fault lines for indicating a failure to external equipment like a redundancy switch.
9.1.1 Applicable Documents
Applicable specifications, as referenced herein, include:
EN 80053-9 Interfaces for CATV/SMATV Headends and Similar Professional Equipment
RS-422 Electrical Characteristics of Balanced Voltage Digital Interface Circuits
EIA-530 High Speed 25-Position Interface for Data Circuit – Terminating Equipment
ETS 300 421 Digital Broadcasting Systems for Television, Sound And Data Services; Framing
Structure, Channels Coding and Modulation for 11/12 GHz Services