UPGRADING REPAIRING PCs

Upgrading the UART Chip 171
OS/2 Method
Use the MODE COMx command from the OS/2 prompt to view
serial port information. Look for an entry called Buffer in the list of
serial port characteristics. If Buffer is set to Auto, the chip is a true
16650A or better. However, if Buffer is set to N/A, it’s an older
16450 chip.
Windows 9x/2000/Me Method
Open the Start menu, and then choose Settings, Control Panel.
Next, double-click Modems and then click the Diagnostics tab. The
Diagnostics tab shows a list of all COM ports in the system, even if
they don’t have a modem attached to them. Select the port you
want to check in the list and click More Info. Windows 95 or 98
communicates with the port to determine the UART type, and that
information is listed in the Port Information portion of the More
Info box. If a modem is attached, additional information about the
modem is displayed.
High-Speed Serial Ports (ESP and
Super ESP)
Some modem manufacturers have gone a step further in improving
serial data transfer by introducing Enhanced Serial Ports (ESP) or
Super High-Speed Serial Ports. These ports enable a 28.8Kbps or
faster modem to communicate with the computer at data rates up
to 921.6Kbps. The extra speed on these ports is generated by
increasing the buffer size. These ports are usually based on a 16550,
16650, or 16750 UART, and some even include more buffer memory
on the card.
Lava Computer Mfg. and Byte Runner Technologies are two of the
vendors that offer a complete line of high-speed serial port cards;
some models also include parallel ports.
Upgrading the UART Chip
Use Table 6.5 to determine where any UART chip might be located
and what you would need to do to replace it.
Table 6.5 Upgrading UARTs
Device Type UART Location Upgrade Method
Internal modem Modem chipset Replace modem
Multi-I/O card Socketed or soldered Replace card; 16550 not pinwith
8250 chips compatible
Multi-I/O card Socketed or soldered Remove 16450 if socketed;
with 16450 chips replace card if soldered