| 摘要 |
<p>An apparatus to which a telephone line can be connected, the apparatus comprising: a first determination unit configured to determine, based on a change amount of a line direct-current voltage from the telephone line per time period, whether the line direct-current voltage is stable; a second determination unit configured to determine whether the line direct-current voltage from the telephone line is a first threshold or lower; and a third determination unit configured to, if the first determination unit determines that the line direct-current voltage is stable and if the second determination unit determines that the line direct-current voltage is the first threshold or lower, determine that the external telephone has captured the telephone line.</p> |
