Modem / Ethernet for a Business PC
If you are planning on using broadband internet, you can use the onboard LAN found on most motherboards these days. If your motherboard does not provide an onboard LAN you can buy a Network Interface Card (NIC) for your computer to connect to your LAN. I use the D-Link DFE-530TX+ (B00004SYNX) and it works perfectly.
However, if you are planning on using dialup service, you will have to purchase a dialup modem. The current standard is V.92 which provides 56 Kbps connection and allows receiving phone calls while connected. The Best Data Products 56FW92 (B000069E1R) provides a V.92 internal modem and also V.44 data compression for faster web page downloads.