MUSICAM USA

Introduction

Most of the Codecs in use at NPR were manufactured by Corporate Computer Systems, now doing business as Musicam USA. The latest standard NPR codec for News gathering is the CDQ-1000 capable of mono operation using either G.722 or Musicam coding.

A more expensive, older unit known as the CDQ-2000 is being used on the permanent links for NPR's Chicago and Los Angeles bureaus. This series only operates on Musicam at bit rates from 56K to 384K. Stereo transmission is possible at bit rates starting at 128K. You'll need at least 192K for good stereo results.

We are starting to utilize a newer series of Codecs knows as the Prima which is capable of higher audio quality but requiring greater transmission bandwidth. It supports G.722, Musicam and Layer III coding. Currently in use on the permanent links for NPR's New York Bureau and the London Office.

CDQ-1000

This codec is designed for use on Switched56/64 lines as well as ISDN, it will use as most 64 Kbits.

You can either set the operating mode with the front panel switches, or allow the unit to auto-detect. MUSICAM USA advises that the units should be operated with only one end of the circuit in Auto-detect. It will work the other way, but it will take longer to sync and you may not end up with the highest fidelity the units can deliver since they may "agree" before reaching the best combination.

Here's what you can expect with the various transmission schemes.

        G.722                          7.5 KHz
        Musicam, 48K Sampling          8.5 KHz
        Musicam, 24K Sampling          10.5 KHz

A universally disliked "feature" of this codec is the blinking of the front panel LEDs when no call is connected. This is normal.

• Micro 66i

When talking to a Micro 66i at 64K, it is important to set the Mode switch to 1.

• Non MUSICAM Layer II

When talking to Level II codecs not manufactured by MUSICAM USA/CCS, it will be necessary to change rear-panel DIP switch 4 on the CDQ-1000 to the up position.

• MUSICAM USA Prima

When communicating with a MUSICAM USA Prima codec, have the far end change the Prima to CCS-O which stands for "CCS Old".

• Layer II Zephyr

To communicate with the newer Zephyrs at Layer II, it is necessary to set the CDQ-1000 for 48K sampling and the Zephyr for L2 Mono send and L2 Rcv

CDQ-2000

This codec was MUSICAM USA's first high-quality stereo audio codec. It is still capable of very good performance for stereo transmission assuming you provide the requisite amount of bandwidth. The design is straight Layer II Musicam with a sampling rate of 48k.

Stereo transmission can be accomplished with as little as 128K transmission speed, but this is by sacrificing separation. The manufacturer recommends that you use a minimum of 192K for stereo. This will require some kind of external inverse multiplexer (NPR does not currently own any external inverse multiplexers).

There are two CDQ-2000s available for NPR remote operations, with a companion unit in Master Control to receive the remote feed. This is an excellent choice when you need 15Khz audio but only require one channel.

• Micro 56 / Micro 56+ / Micro 64 / Micro 66i / Other G.722 Codecs

Non compatible, can't do G.722 Protocol.

• Non MUSICAM USA Layer II

When talking to Level II codecs not manufactured by CCS/Musicam USA, it will be necessary to change rear-panel DIP switch 6 on the encoder of the CDQ-2000 to the up position. The remote codec must be set to operate at a sample rate of 48K.

• MUSICAM USA Prima

When communicating with a MUSICAM USA Prima codec, have the far end change the Prima to CCS-O which stands for "CCS Old".

• Layer II Zephyr

The newer Zephyr's can communicate with the CDQ-2000 in the MUSICAM mode. The only real trick comes at bit rates above 64K. You must have a terminal adapter on the CDQ-2000 that can place or receive independent calls on each B channel. The Adtran ISU 2x64 is just such a TA. This is necessary because the Zephyr terminal adapter does not support the bonding protocol used in the Adtran ISU-128.

Prima

Prima is Musicam USA's new line of audio codecs. It includes both single and dual rack unit designs. The series supports G.722, Layer II Musicam and now Layer III. The units can be configured for use with either internal or external data units making them very flexible. The design does tend to be a bit geeky, making them very flexible but a bit cumbersome to use.

The NPR New York Bureau connection also operates on Prima 110s, but this time at 128K per channel. This provides the same audio performance as the NPR satellite system.

The Prima 110 has one slot which will accept a data interface card or an ISDN terminal adapter. The data interface can operate up to 384K while the single ISDN TA is limited to 128K.

Prima 120

This variation of the one-rack-unit Prima offers some additional buttons as well as LED metering. It is a bit more expensive but easier to use than the 110.This variation of the one-rack-unit Prima offers some additional buttons as well as LED metering. It is a bit more expensive, bur easier to use than the 110.

Prima 220

Careful observers will note that the picture above is actually of the Prima 230, but for our purposes, it's close enough. The 220 doesn't have the spectrum analyzer but they are both bigger and have more buttons and lights that the 100 series.

All the Prima 200s can accommodate three interface cards which can each be an ISDN terminal adapter. This allows them to operate at speeds of up to 384K. Like the 100 series, they can communicate using G.722, Layer II Musicam or Layer III.

There is one Prima 220 in the rack in NPR Master Control. It is at the same time the most flexible and finicky codec in our arsenal. It can communicate with a wide variety of other codecs, some which appear to be incompatible with anything else we have. A big surprise here has been in the ability to link with CDQ-1000s (primarily in Europe) that don't seem to like the vintage of software in our 1000s.

STC has a couple 220s primarily to support the Metropolitan Opera broadcasts. This path constitutes the second backup for the opera after their primary uplink in New Jersey and the NPR New York Uplink at WNYC. This unit has three TA cards allowing it to operate at speeds up to 384K.

RoadRunner

The newest offering from Musicam USA incorporates a mixer, ISDN terminal adapter and mono audio codec into one box. It operates at G.722, Layer II Musicam or Layer III, at data rates from 56K to 128K. NPR has purchased a bunch of these units to replace older codecs in NPR offices around the world.

The RoadRunner Plus incorporates MUSICAM USA's Fieldphone POTS codec into the same box at a considerable price premium. NPR currently owns none of these.

This is obviously a product designed to compete with the Telos Zephyr Express.