This chapter discusses the computer assistance in electronics. The standardization of the PC type of machine and the remarkable amount of computing power that modern examples using the Pentium or equivalent chips can achieve now bring computer-aided drawing and PCB planning methods within the reach of virtually any user. The availability of low-cost computers has made it possible to carry out many tasks in electronics with lesser efforts than was once required. The requirements of a computer for Internet use hinge as much on the modem as on the computer itself. The modem is the hardware item that converts computer signals into tones and vice versa, so that signals can be exchanged using telephone lines that were intended for nothing more than speech. The problems of drawing good clear circuit diagrams have haunted electronics engineers for many years, and can now be solved by the use of any of the low-cost Computer-aided design (CAD) software packages.