User Manual

Remote access
Technical details
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The different access technologies are available with different bandwidth, e.g., DSL (o/+) can be fast or
relatively slow.
Costs
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.
Availability
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.
Recommendations
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.
Migrating from an analog modem-based method
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.
Use of mobile telephone networks (GPRS/UMTS/LTE)
Several suppliers offer GPRS/UMTS/LTE modems, e.g., modems for private use and modems for industrial
applications (also top-hat rail).