Server (RAS) connection. The successful CCNP or CCDP candidate should be able to describe
the signaling and pins used by the cabling and not just the syntax that is required for the
connection. The signaling is just as important because it provides the basis for the physical-
layer troubleshooting that can be needed to establish a connection.
another end device, such as a server, to exchange data. In asynchronous data communications,
end devices are called data terminal equipment (DTE). These devices communicate through
data circuit-terminating equipment (DCE). DCE devices clock the flow of information. In our
case, the modem provides the DCE function to the PC and server.
defines a standard for the interface between DCE and DTE devices. This standard is the EIA/
TIA-232 and was previously referred to as the RS-232-C standard (where the RS stood for
"recommended standard").
single circuit. The PC using a modem is one DTE to DCE path end. The far end DCE to DTE
(modem to server) is another path. Each DTEDCE or DCEDTE connection must be made
prior to data transfer.
the modem, as listed in Table 4-2. The table shows the pins and their definitions. As you read
the table, note the direction of the signal and whether DCE or DTE controls or signals on the
pin.