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Prima LT USERS GUIDE

6-136-13

from 56 to 320 kb/s, also depending on installed Digital Interface

module. Please note that CCSO and CCSN algorithms are both

enhanced MPEG Layer II algorithms but are used when connecting to

older CCS Audio Products codecs such as the CDQ1000 and CDQ2000

codecs that have not been upgraded to work with standard-compliant

MPEG Layer II encoders.

Select the encoder algorithm at the Encoder display prompt or use the

EAL command from a terminal.

6.1.3.2 PKI Compatibility Mode (G.722 Only)

PKI telephones, manufactured by Philips and in wide use in Germany,

require a special frame structure, and your Prima LT must be set

accordingly to interoperate with these telephones. If you are connecting

to a PKI telephone, select the G.722/H.221 line format, enter the line to

use, and then select either PKIOLD or PKINEW formats. If not connecting

to a PKI telephone, select 1 Ln or Ind. Mono at the Line Fmt prompt.

Alternatively, you can use the CGH command from a terminal.

6.1.3.3 Encoder Line Format

Three line formats are available: Single Line (1 Ln), uses only one of the

two available lines. Dual Line (CCS 2-Line), uses both available lines for

112 or 128 kb/s operation over ISDN. Independent Mono (Ind. Mono)

uses both available lines to connect to two different locations. The

single line mode supports all available bit rates, Dual Line supports

only 112 and 128 kb/s. Independent mono supports only 56 and 64

kb/s operation. The Prima LT will allow only valid line formats for the

algorithm selected.

Since G.722 supports only 56 or 64 kb/s, if G.722 is selected, the choices

for line format are Single Line and Independent Mono. Any MPEG

Layer II algorithm supports all three line formats, and MPEG Layer III

supports only Single Line and Dual Line.

With MPEG Layer 2, an additional line format, H.221 Dual Line

BONDING (H.221 2 Ln) is added for compatibility with other

MUSICAM USA codecs. Instead of using Inverse Multiplexing, H.221

employs a protocol known as BONDING to combine individual 64 kb/s

lines into higher bit rate pipes. Unless compatibility is an issue, under

normal circumstances, H.221 BONDING should not be used since the

overall throughput is less than the N x 64 kb/s due to the overhead

required.

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