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CHAPTER 2: Introduction
2.3 Rate-Conversion Rules
56-to-64-kbps conversion is performed by suppressing bit position number 8.
This bit position coincides with the introduced violation (as shown in Figure
2-9), and thus suppressing it conforms to the requirements of ITU-TSS
(CCITT) standard V.110 for 56- to 64-kbps rate conversion. The suppressed
bit can be used for RTS-DCD end-to-end signalling or for a secondary async
channel. North American T1 (1.544-Mbps) applications require that this bit
position be set to a binary “1.” You can do this easily by leaving the RTS pin
open (not connected).
48-to-64-kbps conversion is performed by suppressing bit positions number 7
and 8. The suppressed bits are used in the same way as those suppressed for
56-to-64-kbps conversion.
2.4 Physical Description
The G.703 Codirectional Converter is a standalone unit. The unit is designed
for installation on top of a bench or a shelf, but can also be mounted on a 19-
inch rack with the proper adapter kit. One or two standalone units can be
installed together.