
84 Principles of Synchronous Digital Hierarchy
Cost has not been compared, as the cost for any type of code will vary from
application to application. For example, deploying the Manchester code on
short distance cabling of LAN is not at all costly as the available bandwidth
on the used cable pairs is fully dedicated to this application. However, the cost
of deploying the Manchester code on a long-distance link on radio media will
be considerable, as the cost of the frequency spectrum itself will be doubled.
4.2.7 Multilevel Line Codes
To increase the bandwidth efciency of the system, a multilevel line code is
sometimes used. A multilevel li