control circuitry an infrared transmitter a battery set and a holding stand the keyboard set is pressed to generate signals to the control circuitry that converts the signals and transmits keyboard data to pdas with infrared transmitter the existing pdas infrared receiver can receive data accordingly the direction of the infrared transmitter on the keyboard can be adjusted to fit all the pdas with different specifications application_number US 23341202 A description referring to fig1 and fig2 the present invention is composed of a keyboard set 10 a control circuitry 20 an infrared transmitter 30 a battery set 40 and a holding stand 50 a pda 60 with an infrared receiver 61 can be placed on the holding stand 50 as shown in fig3 the battery set 40 offers the keyboard set 10 power when the keyboard set 10 is pressed and generates signals the control circuitry 20 processes those signals and transmits out the processed signals through the infrared transmitter 30 wirelessly to the pda 60 such scheme can input characters to a pda 60 the infrared transmitter 30 is installed inside a side housing 52 of a revolving arm 51 on the back of the holding stand 50 by adjusting the direction of the revolving arm 51 the infrared transmitter 30 faces the corresponding infrared receiver 61 of the pda 60 with the best angle based on the structure described.