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Do USR modems work on digital phone lines?
Yes on current "digital" lines, but they do not work on the old PBX lines.
In our documentation, we have provided a cautionary statement referring to digital phone lines (PBX) that may cause damage to our modems. The USR modems have advanced protection mechanisms that prevent such damage.
The intent of the warning refers to older private branch exchange systems which provide an analog line but sometimes use high voltage pulses for advanced features. These high voltage pulses had the possibility to damage older modems which did not have advanced protection mechanisms. These private branch exchange systems were often referred to as being "digital". Therefore, the reference to a digital line was made.
Today, telephone lines are often marketed or advertised as digital phone service. In this case, the electrical characteristics of these phone lines are still analog. Our cautionary statement was not intended to cover this case. USRobotics ensures that our modems are compatible with phone systems all over the world.