What type of handshaking you need?
I'd suggest to use VISA instead. Serial port init is an old style vi, and there are VISA serial replacement vi's as well as VISA manuals, describing these details.
....quote from LV online help
input XON/XOFF is a software handshaking protocol you can use to avoid overflowing serial port buffers.
Default value: FALSE
input HW Handshake On the PC and SPARCstation, Input HW Handshake corresponds to Request To Send (RTS) handshaking.
Default value: FALSE
input alt HW HShk On the PC, Input alt HW HShk corresponds to Data Terminal Ready (DTR) handshaking. On the SPARCstation, this parameter is ignored.
Default value: FALSE
Output XON/XOFF is a software handshaking protocol you can use to avoid overflowing serial port buffers
.
Default value: FALSE
Output HW Handshake On the PC and SPARCstation, Output HW Handshake corresponds to Clear to Send (CTS) handshaking.
Default value: FALSE
output alt HW HShk On the PC, Output alt HW HShk corresponds to Data Set Ready (DSR) handshaking. On the SPARCstation, this parameter is ignored.
Default value: FALSE
XOFF byte is the byte used for XOFF (^S).
Default value: 0x13
XON byte is the byte used for XON (^Q).
Default value: 0x11
parity error byte If the high byte is non-zero, the low byte is the character that is used to replace any parity errors found when parity is enabled.
Default value: 0
......end quote
there is useful resource:
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/5113574c27098cf7862568210005f0dd?OpenDocument#5
Sergey