The following information will make it easier to calculate the expected communication costs:

Using a standard analog phone line and the internal modem from the A840, the time it takes to establish the GSM connection with the RTU will be between 30 and 45 seconds. This time is NOT needed by Adcon, but by the GSM protocol for proper device handshaking!

Add to this the time to transmit the data: ~ 40 seconds for slot 900 / x on A733GSM using an external GSM modem (1) connected to the serial port of the A840, the time to establish the connection is reduced to 20 to 25 seconds, the time for data transfer remains the same: ~ 40 seconds for slot 900 / x on the A733GSM

NOTE: to build a data connection to your RTU you need the data number of your SIM card. The GSM standard assigns by default 3 numbers to a SIM card: a voice number, a fax number, a data number. Make sure your provider offers CSD services and delivers a data number with your SIM card!

NOTE: Watch out when using cheap routers! They might prevent you from initiating data calls by simply cutting off the required prefixes.