HP Vectra Technical Reference Manual page 400

Speaker Control Circuit
1/ 0 port 61 H, bit 0 gate
output .....-----1 clock 1.190 Mhz
I/O port 61H, bit 1
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Figure 0.1
The sound related EX-BIOS functions are the recommended method of accessing the speaker
functions (see Section 9).
0.7 Keyboard I/O Ports
~
Keyboard Command Port (64H): Used to write commands to the 8041 keyboard controller.
Keyboard Extended Command Port (68H): provides a data/command path to the 8041 not
conflicting with the industry standard I/O Ports 60H and 64H.
KBD Request Port (69H): Allows communications between the 8041 and the EX-BIOS service
request (SVC) routines.
Keyboard Handshake (6AH): The single bit write only port provides a mechanism for the 8041
keyboard controller to indicate the last service request (SVC) has been handled.
HP-HIL Controller (6CH thru 6FH): This set of I/O Ports provides the communication mechanism to
the HP-HIL controller.
0.8 Real Time Clock Ports
Real Time Clock and CMOS RAM ports 70H and 71 H provide the interface to the MC 146818 real
time clock (RTC). See Appendix C for further details.
I/O Port Map 391