As far as i'm aware of, SERIN will never work @19200 bauds

You must use HSERIN with the internal USART

@4mhz
Code:
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 12 ' 19200 Bauds
DEFINE HSER_CLOERR 1
@8MHZ
Code:
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 25 ' 19200 Bauds
DEFINE HSER_CLOERR 1
@20MHZ
Code:
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 64 ' 19200 Bauds
DEFINE HSER_CLOERR 1
But there's an alternative that could work, see DEBUG in the PBP manual