User Manual

Remote access
Technical details
15
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The costs are divided into monthly basic costs and usage costs. To optimize
costs, analyze your usage profile, that is, how many times per month do you use
it and how much data do you exchange per use.
A data flat rate ensures that the costs are capped. Choosing an inappropriate
rate plan for a mobile subscription could result in high costs.
RF-based links and all mobile network-based transmission standards can
suffer from transmission problems due to bad weather especially at the cell
border. The bandwidth that can effectively be used in the project can vary over
the day, because the bandwidth is shared by all users. The bandwidth
variations for cable-based technologies are lower.
To ensure a reliable remote access, use cable-based technologies even if the
cost is slightly higher. Use mobile networks or RF-based systems only if no
alternative is available. If you require a high availability remote access, you can
additionally establish a mobile network-based link as a fallback solution. To do
this, use a router that offers both a DSL and a GPRS/UMTS/LTE modem.
Every remote access can be attacked. Note the safety measures in the
document
IT Security in Desigo Installations (CM110663).
Access to the PXC..D/-U automation stations via Xworks Plus (XWP) can be
protected with a password (password property for remote access
[RemAcpwd]). You can enter the password in the Device Property dialog in
XWP.
Analog modems should not be used in new installations and are not future-
proof due to the migration of the networks to Voice over Internet Protocol
(VoIP).
ISDN also is not a future-proof technology and should therefore not be used.
If DSL is available, use DSL. Otherwise, use other cable-based internet access
networks. If you cannot use such a network, use a mobile network or an RF-
based access.
If a project is based on LON, use the PXG3.L router, to connect the remote
access on the IP side of the router.
15.3 Technical details
DSL
The DSL modem must match the used xDSL technology and should be
purchased in the country of use. DSL connections can use different coding
methods, which differ from country to country.
A modem either has one RJ45 connector for connecting the router or has a
built-in router. The router must be configured. The modem needs an access
code from the Internet Service Provider (ISP).
If the telephone line is to be used for DSL and telephony, a DSL splitter that
splits the phone and data signals is necessary.
TV cable-based method
The operator provides the modem. Sometimes, you have to configure the
modem. Usually, the cable operator provides a preconfigured modem or the
modem configures itself automatically when you connect it for the first time.
The modem has an RJ45 connector to connect it to the IP network (the router)
or a built-in router. The router must be configured. Sometimes you need to
enter an access code received from the operator.
A separate DSL splitter for splitting TV and data signals is not necessary.
Metro Ethernet
Metro ethernet is usually not implemented in a BACS project and is therefore
not described in this document.
Costs
Availability
Recommendations
Migrating from an
analog modem-based
method