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Entry type: FAQ Entry ID: 1096710, Entry date: 06/11/2013

What should you watch out for when selecting a modem for use with SIMATIC S7 TeleService?

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For SIMATIC TeleService you need one modem on the Service PG/PC and under circumstances one modem on the TS Adapter on the remote plant. The latest TS Adapter versions have an integrated modem (as from TS Adapter II), but for special cases also allow you to connect an external modem via an RS232 serial interface.

You can use virtually any standard, commercially available modem with SIMATIC TeleService provided it understands and works with the Hayes "AT" commands.

  1. Selecting a modem for the TS Adapter on the plant
    We recommend using one of the latest TS Adapter with integrated modem. You should only connect an external modem to the TS Adapter if the integrated modem is not suitable for the local telephone system or for the purpose intended (sending SMS texts, for example). In the case of all TS Adapter versions (TS Adapter I/II/IE/TS Module RS232), you can only use the serial RS232 interface to connect an external modem. To this you can connect and operate standard modems, ISDN terminal adapters or GSM wireless modems with a serial RS232 interface. It is not possible to operate an internal and an external modem at the same time.
  2. Selecting a modem for the Service PG/PC
    Which modem type to select depends primarily on the PG/PC's interface (RS232, USB, for example) and the physical telephone system (analog, ISDN or GSM). Many new PG/PCs no longer have a serial interface (COM), for example, so you can no longer operate such modems or only with an adapter.
    There must also be a device driver installed for the modem you are using on your Service PG/PC, which is supported by the operating system and the modem. The TeleService software has transparent access to the device driver installed in Windows.

If your customer is using an ISDN modem (or "ISDN TA") with an ISDN telephone system on the plant side, the counterpart (the PC/PG side) must also have an ISDN modem installed in an ISDN system. This rule applies to analog modems too and is independent of the use of TeleService. Communication between an ISDN TA (TA = Terminal Adapter) and an analog modem is not possible.

If either the plant or the PG/PC side is using different telephone technologies (ISDN/analog), you can use a hybrid modem. These devices support ISDN and analog technology. They are installed physically on the S0 bus of an ISDN telephone system.
An alternative is to install two separate devices (ISDN and analog modems) on an ISDN telephone system so the PC side, for example, can respond appropriately to the technology of the other side.
An extra A/B converter can be installed in the ISDN telephone system for this purpose. An A/B converter permits you to use analog terminal devices like an analog modem, for example. In this way it is possible to integrate conventional analog terminal device in an ISDN system. For further inquiries on this topic, please get in touch with your telephone system provider.

Buying a modem
When buying a modem, find out whether the modem can be used in the intended country. Modems are still subject to national licensing regulations.
In some cases it makes more sense to buy the modem in the country where it is to be used. This gets around the problem of having the right connectors to fit the local telephone sockets. If an unlicensed modem is used, it may not recognize incoming calls.
Check with the modem manufacturer or dealer whether the modem has or requires an explicit certification for telecommunications.

Worldwide use of the internal modem in the TS Adapter version II/IE/TS module
The modem in the TS Adapter versions TSA II/TSA IE/TS Module II modem is designed to be used worldwide. When installing and operating a modem, please observe the country-specific legislation and special requirements.
A list of countries is given in the manual of each TS Adapter type. This list shows the countries for which telecommunication certification has been made.

A relevant list of countries is also in each of the manuals for the TS Adapter versions TS Adapter II ISDN, TS Adapter IE ISDN, TS Module ISDN and TS Module GSM.

Recommendation for using a modem in conjunction with TeleService and TS Adapter
Below is a list of modem types that are known to support TeleService application in conjunction with the TS Adapter. Experience has been gained from the following sources:

  • System test
  • Own use
  • Positive feedback from users

The TS Adapter used on the plant has the task, among others, of parameterizing the integrated modem or the modem that was installed on the serial RS232 interface (TS Adapter). For this purpose, it sends the following initialization string ex works (AT commands) via the serial cable to the modem.
AT &F E1 L1 M1 Q0 V1 &C1 S0=1 (displayed with spacing for better reading. The initialization string without spacing is stored in the TS Adapter).
More information about this is available in the TeleService manual.
The meanings of the AT commands are available in Entry ID 17907350

External analog modem types with serial RS232 interface

Modem type Init string in the TS Adapter:
(default = AT&FE1L1M1Q0V1&C1S0=1)
devolo MicroLink 56k i (industrial modem) default http://www.devolo.com/

See Entry ID 24045211

Westermo TD-36 (for 35mm DIN rail) default http://www.westermo.de
Westermo TDW-33 (for 35mm DIN rail) default http://www.westermo.de
BM-1000 PRO default http://www.blatzheim.com
Table 01

ISDN modem types with serial RS232 interface

Modem type Init string in the TS Adapter:
(default = AT&FE1L1M1Q0V1&C1S0=1)
devolo MicroLink ISDN  i (ISDN modem/ terminal adapter for industrial use with RS232 interface) default http://www.devolo.com/
SINAUT MD 4 ATE1L1M1Q0V1&C1S0=1 See Entry ID 16971000
Westermo IDW-90 (for 35mm DIN rail) default http://www.westermo.de
BM-33k6/ISDN per hybrid modem default http://www.blatzheim.com
Table 02

The requirement for applying TeleService is that the ISDN devices listed here are addressed with a modem driver supporting the B channel X.75 protocol. This device driver is normally included in the modem delivery package (disk, CD, configuration tool). With few exceptions only, devices are set to the X.75 protocol ex works.

ISDN TAs for the PG/PC side

ISDN TA Name Remarks
AVM FRITZ! Card PCI *) http://www.avm.en
AVM FRITZ! Card USB v2.x *) http://www.avm.en (discontinued)
BM-33k6/ISDN per USB. Hybrid modem with RS232 serial interface and additional USB interface http://www.blatzheim.com
ISDN TAs, for which there are not 64-bit drivers. You must install a standard modem (33600 bps, for example) and set the protocol (X.75, for example) and MSN under Properties > Advanced.
ISDN-TA PrimuX USB http://www.gerdes-ag.de/en/products/primux/soho/

Required driver: PrimuX USB
Also compatible with MS Windows 7 64-bit.

Table 03
Remarks on the AVM FRITZ!Card:

In order for TeleService to use the AVM FRITZ!CARD optimally you must also install the AVM ISDN CAPI port driver. If this driver is not already installed on your PC, you can download the driver directly from the download area at AVM (http://www.avm.en).
The AVM ISDN CAPI port driver for various Windows operating systems is available there under "Download > More Downloads > For the FTP server > Programs > capiport"
The driver incorporates your AVM hardware into the operating system of your PC. A specific CAPI driver is required for each operating system. The CAPI 2.0 interface of the driver controls the communication of the application programs with the AVM hardware and has all the performance features of the EURO-ISDN connection.

You can use the AVM ISDN CAPI port driver in the 32-bit versions of the Windows XP, Windows Vista and Windows 7 operating systems, but not in their 64-bit versions.

After installing the AVM ISDN CAPI port driver you have various virtual modems (software modems) at your disposal. The three listed below are suitable for the TeleService application.

(only in 32-bit Windows)
AVM ISDN Analog Modem (V.32bis) Suitable for establishing connections to a TS Adapter with internal or external analog modems.

1. The transmission rate is very slow (9600 bit/s - 14400 bit/s).
2. The callback from the TS Adapter to the AVM FRITZ!Card is unreliable.

AVM ISDN Mailbox (X.75) Suitable for establishing connections to a TS Adapter with internal or external ISDN TAs.

None known

AVM ISDN Custom Config Suitable for establishing connections to a TS Adapter with internal or external GSM modems.

THe AVM ISDN Custom Config modem must be configured in Properties > Advanced with the AT command ATS31=2 on V.110.

Table 04

If you do not install the AVM ISDN CAPI port driver you only have the AVM NDIS WAN CAPI driver available.

(in 32-bit and 64-bit Windows)
AVM NDIS WAN CAPI driver Suitable for establishing connections to a TS Adapter IE with internal or external ISDN TAs.

1. Not suitable for connections to a TS Adapter I or TS Adapter II.
2. The callback from the TS Adapter IE to the AVM FRITZ!Card does not work!

Table 05

Analog modems for the PG/PC side

Modem name Remarks
USRobotics 56K USB Modem, Model 5637 http://www.usr.com
Modems, for which there are not 64-bit drivers. You must install a standard modem (33600 bps, for example) and set "Ignore dial tone" under Properties > Advanced. In most modems this is done with the AT command ATX3.
Table 06  

GSM modem for the TS Adapter versions TS Adapter II and TS Adapter IE

Modem type Link
SINAUT MD720-3 GSM/GPRS MODEM See Entry ID 30330207
Table 07

General note
It may be quite possible that one or the other type of modem is no longer commercially available. In the course of technological advancement of the devices, older types are replaced by new ones.

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