The Comtech SDM-300A is a direct replacement for many Comtech EF Data modems.
Fully configured, the Comtech SDM-300A will meet or exceed all of the applicable requirements in IESS-308, 309, and 310 and is available with a full range of industry standard digital interfaces.
Maintaining Comtech EF Data's excellent history of modem compatibility, the SDM-300A is a direct replacement for many Comtech EF Data modems. When configured properly, the SDM-300A can be installed to communicate with or replace the following Comtech EF Data modems:
All Comtech EF Data redundancy switches (1:1 or M:N) can be used with the SDM-300A, making field replacement or upgrades of existing systems easy and cost effective.
Comtech EF Data's SDM-300A employs Fully Accessible System Topology (FAST). This technology provides a costeffective approach to upgrading satellite modem configurations. FAST is an exclusive, industry-first feature that eliminates the need to purchase options before they are needed.
An SDM-300A base modem includes the following features:
BPSK and QPSK
Viterbi or Sequential decoding
Single data rate
IF range from 50 to 180 MHz (1 Hz steps)
Enhancing the SDM-300A's performance is easy. Additional features are added quickly on site, using the FAST access code purchased from Comtech EF Data. To enable these features, simply enter the code at the front panel.
Base unit enhancements include:
Changing from single rate to variable rate
Extending the data rate from 512 kbit/s to 5 Mbit/s
Viterbi and Sequential decoding
Reed-Solomon concatenated Codec
IDR / IBS / D&I / AUPC / ASYNC
BUILT-IN SELF TEST
Comtech EFData's unique built-in self test feature allows the SDM-300A to complete a bit error rate (BER) measurement without the use of expensive noise generators and BER test equipment. The built-in self test:
Provides fully functional modem testing with noise
Displays pass or fail results
Establishes modem confidence
Eliminates BER test equipment
When commanded to the self test mode through the front panel or remote port, the SDM-300A disables the Tx and Rx IF ports and internally tests modulator, demodulator, and interface functions by means of a BER measurement. The BER measurement is achieved via an internal IF noise generator and BER test equipment built into the SDM-300A.
System Specifications (Fully Enhanced)
Operating Frequency Range
50 to 180 MHz, in 1 Hz steps
Digital Interface (Standard)
EIA-232, EIA-422, and V./35 (25-pin D)
Digital Data Rate
2.4 kbit/s to 5 Mbit/s, in 1 bit/s steps
64 kbit/s to 5 Mbit/s (8PSK)
4.8 kbit/s to 2.5 Mbit/s
Modulation and Coding
Viterbi(K=7) Sequential Concatenated Viterbi and Reed-Solomon Turbo Uncoded