- MB
- Multiple Branch Generally means the telco circuits one dials and talks
on rather than the ones one sends programming through. Gets its name from, for example,
the 2500 line in Master Control which appears on more than one key telephone (when we had
key telephones) and thus is multiple-branched.
In NPR remote-broadcast parlance, refers
to any circuit used to communicate with the remote crew whether it is an off-premises
extension or an outside line.
- MCI
- A provider of long distance voice and data services. You can force any call on MCI by
preceeding the phone/IDSN number with 10-222.
- Modem
- A MODulator/DEModulator is used to connect a data device to a
transmission channel.
- Musicam
- In North America, Musicam is the trademarked name of a propriatery digital transmission
protocol. It is owned by MUSICAM USA (formerly know as CCS). In Europe, Musicam is
synonymous with ISO MPEG Layer II. The two protocols are similar, but distinctly
different. For our purposes here, we refer to Musicam (TM) as the propritary
implementation of Layer II.
The particular box NPR has chosen can operate on one 56K to
384KBit line or two 56 or 64KBit lines. The resulting audio depends on the number and
bit-rate of lines used plus the mode the unit is operating in.
Our existing systems are capable of one 15kHz, two 8.5KHz Mono channels or 15KHz Stereo
with two 56 or 64KBit lines. The Telos Zephyr provides better
frequency response and separation at the same bit rate (using ISO MPEG Layer II) but
loses this advantage at higher rates.
Musicam is currently in use for NPR Washington interconnection with Los Angeles,
Chicago and London as well as dial-up service for WDCU.
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