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43: Codecs I Have Known, Part 3:  MPEG   8/8/13 by Dave Immer

This is the last installment of my ISDN retrospective covering codecs popular in the US. Whereas APT-X (legacy units) and AC-2 can generally be associated with a hardware brand, with MPEG it becomes much more diffuse, as many manufacturers license the various MPEG flavors.

Musicam CDQ2000: My first ISDN codec. This unit, along with the DolbyFax and the APT DSM100 were the main full bandwidth systems to become popular and all are still in use today. These systems were revolutionary in the way they set in motion the transformation of much voice actor contribution from a strictly local endeavor to a wide-area work mode. The CDQ2000 has 1 algorithm – MPEG layer II, which became and remains the “street standard” for MPEG compatibility.

Musicam Prima (both CDQ and LT): A reliable workhorse that typically runs for years without a hiccup, it is quite popular among MPEG codec users. The smaller mono-only RoadRunner can also be included in this group.

Suprima (including RoadWarrior): The new generation of codec type, this family of models features dual-mode (ISDN & IP) capability, browser remote control, auto-sensing decoder and advanced IP streaming protocol.  While the ISDN mode has the reliability one would expect, the Suprima-family IP mode can deliver an ISDN-like experience connected to a compatible unit over the internet. The top models include the full range of APT-X and AAC algorithms in addition to the MPEG flavors as well as G.722/ G.711 (POTS compatibility) plus linear audio.

Telos Zephyr (both classic and Xstream): The most popular MPEG-based ISDN codec out there, due, in part, to it’s excellent user-friendly front panel features and customer support. Telos was a major early player in the codec market. The Zephyr has always been able to operate in the “voice” mode, allowing POTS phone-patch connections.

Other compatible MPEG brands include Mayah, TieLine, Comrex, AudioTX, AEQ, Prodys.