PLC programming with modem

[Marjan]

Hello! I have a problem with programming my plc Momentum. I have tryed to pragrammed (download my programme) it through gsm modem (both are Siemens TC35i - 9600, 7, e, 1). But in the midle of the downloading i get an error Timeout response or sometimes ?You are not logged into a PLC? and downloading is canceled. I have tryed the same thing with analog modem and i got the same thing. Is it even possible to download so much data trough modem? With which gsm modem will be possible? Thank you