Can I connect two phone lines to this modem?

The modem is connected to a wall jack that has two lines. When I connect a phone to the modem, line 1 works, but line 2 is dead.

The modem can connect to only one line at a time. The modem's phone jack is designed to connect a telephone to the same line as the modem. The phone jack will not connect to a second line of a wall jack.