| 摘要 |
A packet communication card enables consumption of a battery for a portable digital telephone to be reduced by changing supply power for the portable digital telephone in accordance with a state of the portable digital telephone. The pocket communication card which is connected to the portable digital telephone, and which is provided with a COM port necessary for implementing packet communication, is inserted into a data terminal equipment to be used. There is reduced consumption of the battery for the portable digital telephone by selecting to be changed one power source which is a power source of power sources being at least more than one for supplying power to the portable digital telephone in accordance with state of communication of the portable digital telephone. A switch implements change of supply power. |
