VeEX MPA User Manual page 828

MPA_e_manual_D07-00-129P_RevA00
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Protocol
A specific set of rules, procedures, standards or agreements as to exactly how data is to
be formatted and transmitted between two computers, devices or facilities in a network.
Protocol Control Information
Information exchanged between corresponding entities, using a lower layer connection,
to coordinate their joint operation.
Protocol Data Unit (PDU)
A segment of data generated by a specific layer of a protocol stack; usually contains
information from the next higher layer encapsulated with header and trailer data
generated by the layer in question.
Pseudo-Random Bit Sequence (PRBS)
See PRBS
PTI
The GFP payload type identifier (PTI) is a 3-b field that indicates a data frame (PTI = 0)
or a management frame (PTI = 4) with other values currently undefined. See also PFI.
Pulse Code Modulation (PCM)
The most common method of encoding an analog voice signal into a digital bit stream.
First, the amplitude of the voice conversation is sampled. This sample is then coded into
a binary (digital) number, consisting of ones and zeros. The voice signal can then be
switched, transmitted and stored digitally. The most common PCM method is to sample
a voice conversation at 8000 times a second. The theory is that if the sampling is at
least twice the highest frequency on the channel then the result sounds OK. Thus, the
highest frequency on a voice phone line being 4,000 Hertz, the sample of it must be at
8,000 times a second. These 8,000 bytes sampled per second then become 64,000 bits
per second, the base signal rate for a DS-0 signal, a single phone conversation.
PTR
See Pointer.
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QOS
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