So your serial data is on the same pin as your Buzzer?

Did you set HS_OSC fuse for your F877?

Your PIC16F628 use the internal OSC? Sure the Config fuses are set for it?

As Dave suggested, you want to make sure your qualifiers match on Both Side. Two way here.. or you change #55 to 55 in your SEROUT line, or you change B0 to #B0 in your SERIN line.