CSD call / replacement of an analogue modem

CSD call / replacement of an analogue modem

For the data call on GSM, UMTS or 3G also called CSD (circuit switched data) and replacement of an analogue modem to a wireless cellular modem please note the hints as below:

  • Activate auto answer and fixed baud rate may be. Store your profile with AT&W.
  • Use SIM card preferably offered by T-Mobile Germany. Deactivate the PIN query. Please note that Vodaphone Germany does not allow the deactivating of the PIN query as standard. For other countries we can help with recommendations on request by email.
  • Standard SIM cards (Pay as you go, prepaid and SIM cards with subscription) support outgoing data calls only. Please make sure to have this service activated on your SIM card by the GSM operator for the first tests. For incoming data calls you will need a special subscription. Pay as you go/ prepaid SIM cards often do not support incoming data calls.
  • In the final application we recommend a SIM card that support “Data Only”. Data Only SIM cards of T-Mobile supports incoming and outgoing data calls and GPRS and SMS as well. We also can help with special tariff contracts and European data flat rates.
  • Force bearer type with AT+CSNS=4 to data permanently so that by multi numbering and call from an analogue modem a data connection can be set up. Please note that worst case the GSM base station sends no bearer code. The default bearer in most GSM modems is voice. If no bearer code will be forwarded, the modem will connect a voice call and this will then end in a “No carrier” message at the calling modem.
  • Please take care that the GSM operator that you will use supports CSD data calls. In USA, Canada and by a few operators in South America CSD is not supported. They offer packet switched data on GPRS (GPRS) only!
  • Take care that some GSM networks are supporting V.32 and other the V.110 protocol better. The protocols can be changed by using of AT+CBST. If the changing of the parameters of the selected protocol can optimise the communication. If you are able to change the settings of used protocol by SMS, then you will be able to optiimise the protocol and parameters remotely by SMS.

For further question on CSD, modem call, analogue modem to GSM connection, ISDN, V.32, multi numbering, single numbering just give us a call or better an email. Normally we heard about all issues around GSM to GSM, GSM to PSTN analogue, GSM to ISDN, ISDN to GSM, PSTN analogue to GSM data communication by our last 15 years in consulting and support in GSM and GPS communication before. We will be glad to support you too.

Updated: 2010-09-02 — 9:24 AM

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