Unfortunately, the telephone line conditions in many foreign countries are marginal, at best. International connections via microwave, satellite and underwater cables may create adverse line conditions that interrupt data transfer, causing your modem to error, retrain or drop the line. Faster modem communication speeds require clean, high quality phone lines.
Noisy lines can cause high-speed transmissions to error or even drop the line.
Under optimal line conditions the encoding technique, known as data compression, can speed up data transfers. However, under adverse line conditions data compression can have a negative impact on connections. Disabling compression can reduce errors by slowing down the data flow.