The MMM-4682 and MMX-4682 from IRT Electronics are part of a family of data transcoders for converting between the commonly used MPEG2 Transport Stream formats for video distribution in the broadcast industry.
With the MMM-4682 data transcoders up to four ASI and one RS232 data signal can be combined together and converted into 155Mb/s G.703 (STM 1) electrical CMI and optical NRZ signals.
The sum of the ASI input payload rates can be anything up to 148 Mb/s. Inputs may be 188 or 204 byte packet length, burst or continuous, and may have energy dispersal scrambling, interleaving and/or Reed Solomon bytes included.
The MMX-4682 data transcoders separate the 155 Mb/s G.703 signal back into the original four ASI signals (at their original rates) and the RS232 data signal. The ASI outputs are suitable for Single Frequency Network use, in that there is no data rate conversion or PCR restamping of the ASI streams.
Inputs are automatically equalised for lengths of up to 200m of Belden 8281 or equivalent cable.
RS232 uni-directional data may also be sent on the same link. It can pass rates up to 19.2 kb/s with any combination of start/stop & parity bits. The data rate does not affect the payload available for the ASI streams.
The MMM-4682 and MMX-4682 data transcoders are designed to fit IRT’s standard Eurocard frames and may be used alongside any other of IRT’s analogue or digital Eurocards.