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SICAM Q80 7KG8080
Power Quality Recorder SICAM Q80 7KG8080, System manual
E50417-H1076-C420-A2, Release 12.01.2015
7.1.3
Modem connection (TCP/IP with PPP)
What is a PPP connection?
The abbreviation PPP means Point–to–Point Protocol. As the name indicates, this protocol concerns single point to
single point connection (i.e., one client and one server) as opposed to Ethernet, where any amount of subscribers are
connected together via the Ethernet-bus. The client is always the one to set up the connection and to register with the
server. The server checks the client's authorization and transfers to the client all information necessary for
participating in network communication. After this, both parties configure their network interface; a connection then
exists between the two. The PPP-protocol manages this preliminary procedure; it does not handle the actual
communication! Instead, the PPP-protocol can be viewed as building a sort of "tunnel" between the parties and
packaging the actual network communication protocol, for instance TCP/IP.
In a TCP/IP-based network, the individual subscribers are distinguished by their personal IP address. Strictly
speaking, the address is not assigned to the PC or device, but to the network interface. After all, if a PC has two
Ethernet connections, it can have two IP-addresses.
IP addresses, then, can be assigned not only to Ethernet interfaces but to any network interface which is able to
transfer data according to the IP protocol. In this sense, even the WINDOWS
Dial-up Network
(with PPP-option
activated) represents an IP interface. Consequently,
the Dial-up Network
is also indicated in the
Control Panel
under
the icon
Network
as a
Dial-up adapter
. And that is where it must be configured as an IP-interface. The fact that a PPP-
connection is what is meant by the
Dial-up Network
is not relevant at this point. The
Dial-up Network
and thus the
actual PPP connection is administered under the icon
My computer
on the WINDOWS Desktop.
Physically, such point-to-point connections are serial connections. In the simplest case, the two PPP-subscribers are
connected via a zero modem cable. However,
SICAM Q80 7KG8080
is not designed for this; instead, PPP is used
exclusively to set up a connection via modem2 (and the telephone network).
In summary, PPP in conjunction with TCP/IP serves to connect two PC/devices or networks via a serial modem
line. The PPP-connection remains transparent for the network subscribers. The PPP connection is a property of
the
Dial-up Network
.
2
The modem, e.g. INSYS Modem 336 /56k /56k UL is optional (not standard included).
7.1.3.1
SICAM Q80 7KG8080 via PPP
For connection via PPP, the device
needs a serial interface in addition to the Ethernet connection. This serial interface
can be connected to a modem. The measurment device is in this case the PPP server, the control-PC the PPP client.
That means that the PC calls the device to establish a connection. TCP/IP is used as the network data transfer
protocol.