Solution:

If user has the default setting on PCX-797, then the problem was caused by I/O address confliction between PCX-797 and PCLSTEST program. Because the default I/O address of PCX-797 and PCL-818 series cards are 300H, the test programs (PCLSTEST or TESTPROG) will write/read 300H when selecting the card type. Thus, PCX-797 will not works correctly. However, the default I/O address of PCL-812 is 220H. Therefore, the test program will not cause the same problem. Please set the I/O address of PCX-797 to other address and check the problem again