Nextar MA99T - Manual (Page 21)

Select the file menu to choose the Input Data to find the file (TelAddbk.
dat) in your mp3, and then press the open button.
Fill in team name in the blank and press the Append Grouping button:
Select the team you added, and then key in the Name and the TEL you want to add.
Press the New Card button and you can see the name and Tel No. in the right blank.
Add the whole information as the above steps:
Press the Save button and Quit. Disconnect the mp3 to PC.
Enter the main menu to select Telephone mode and you will find you added Tel information.