HP 24SII - Manual (Page 37)

If you are interfacing a DCE device to the Model 24SII DES (DTE),
you must use a one-to-one or straight cable as shown in
Figure 3 on
the following page. If you are interfacing a DTE device to the Model
24SII DES (DTE), you must use a crossed cable as shown in
Figure 4
on the following page.
When using XON/XOFF protocol, it may be desirable to use cables
with only Tx, Rx and GND connected. Input handshaking lines are
enabled if nothing is connected allowing the system to operate with
only Tx, Rx and GND connected.
CAUTION: Do not attempt to use a serial cable on a parallel port.
Since an EIA-232 serial port usually carries a potential of +12 and -12
volts, plugging a serial cable from that port into a parallel port may
cause damage to the parallel port.