I'm unable to configure the VOIP with Windows XP using a com port.This is a known issue when configuring VOIPs using Windows XP. Configuring the VOIPs IP address with Hyperterminal will allow you to access MultiVOIP configuration over IP, from a computer that is on the same network.
Connect the VOIP to Hyperterminal at 19200, 8-N-1, no flow control. Type "login" (without quotes) from the Hyperterminal prompt and press [enter] to bring up the telnet configuration menus. Configure the VOIP IP address in the following manner:
Choose  Voice over IP Configuration; press [Enter], then
 Protocol Stacks; [Enter], then
 Internet Protocol; [Enter], then
 IP Port Configuration; [Enter], then
 Ethernet; [Enter], then
Choose IP Port Node Address from the<<IP Port Setup>>menu; [Enter]
Type the IP address you want to assign the VOIP; [Enter]
Choose [A] Apply; [Enter]
Press Escape [Esc] four times to get back to the main menu
Choose [S] Save And Reboot and press [Enter] to save the IP address and reboot the MultiVOIP.
Select Configuration Port Setup from the MultiVOIP configuration software program group on your computer. Choose IP as Communication Type. Enter the IP address you configured in Hyperterminal where it asks for MultiVOIP IP Address. Click OK to close this window. Run MultiVOIP Configuration from the voip software program group.