Solution:

Befor you use PCM-3640, please configure CMOS setting of your PC. Note: PCM-3640 does not provide "Share IRQ" function. That means you need to use different IRQ for different COM ports ! I. PC CMOS Setting Please check the setting in " Intergrated peripheral" of CMOS setting. Make sure your COM ports are configure with proper IRQ and IO address normally. You may need to disable PC on board COM port to prvent conflict of IRQ channel. Note: The standard COM port resourecs default are: COM1 IRQ4 Address: 3F8 COM2 IRQ3 Address: 2F8 COM3 (IRQ10) Address: 3E8 COM4 (IRQ 5) Address: 2E8 You may double check the setting form system boot up configuration window.If you need to use more than 4 COM ports, please make sure that your COM port use different IRQ and address. an easy utility to check is the DOS MSD.exe. II. COM port function test guide A.How to setup serial port for Windows 95/NT? [ For Windows 95 ] 1. [Start] -> [Setup] -> [Control Panel] -> [Add New Hardware] 2. Click [Next], choose [N]ot to do auto search new hardware. 3. Click [Next], choose [Connection Port (COM & LPT)] Hardware Type. 4. Click [Next], select [Standard Connection Port Type] for manufacurer and [Communication Connection Port] for model. 5. Click [Next], then the default IRQ and IO Address will be shown. Click [Done]. Up to this point you have added a port to system without correct IRQ and can repeat step 1 to step 5 to add as many ports as you want (Max. 128 port). 6. [Control Panel] -> [System] -> [Device Manager] 7. Select your new COM?, then [Resource] 8. Select the ??? as [Basic Configure 8]. 9. Double click on IRQ to type in (select) the hardware IRQ, then [OK] 10. Double click on I/O rage to type in (select) the hardware I/O, then [OK]. Repeat step 6 to step 10 to setup each port correctly. 11. Click