Hi, I am just started to learn C++ programming and was wondering if anyone could please help with the following error from the codes that follows: Error: v24.cpp(164): Error! E166: col(17) cannot convert right pointer to type of left operand From: if (port == COM1) { oldintv = _dos_getvect(0x0C); <- Error on this line? _dos_setvect(0x0C, newintvcom1); outp(0x0021, (intenable & 0xEF)); } I am using Open Watcom C/C++ compiler and this is the error message: "The C++ language will not allow the implicit conversion of unrelated class pointers. An explicit cast is required: Example: class C1; class C2; void fun( C1* pc1, C2* pc2 ) { pc2 = pc1; }" The source code is (i think) 16-bit and therefore I am using the win16-bit settings on the Watcom to compile the code. Any advice and help is much appreciated, thanks Best Regards Casey