HP Vectra Reference Manual page 149

Modem Status Register (XFEH)
This register provides information on the current state of the
control lines from the modem or device.
~
Bit Data Definition
0 1 Set if clear to send signal (C8) input changes state.
0
Reset when the Modem Status Register is read.
1 Set if data set ready (CC) input changes state.
0 Reset when the Modem Status Register is read.
2
Set when the ring indicator (CE) input changes from
low to a high state.
D
Reset when the modem stauts register is read.
3 Set if the received line signal detector (CF) input
changes state.
0 Reset when the Modem Status Register is read.
4 Set when the CB input is active. However, if the
~.
modem loopback is enabled, this bit is equivalent to
CAofXFCH (bit 1).
0 Reset when the C8 input is inactive.
S
Set when the CC input is active. However, if the
modem loopback is enabled, this bit is equivalent to
CD of XFCH (bit 0).
0
Reset when the CC input is inactive.
6
Set when the CE input is active. However, if the
modem loopback is enabled, this bit is equivalent to
-- OUT1 of XFCH (bit 2).
0 Reset when the CE input is inactive.
7
Set when the CF input is active. However, if the
modem loopback is enabled, this bit is equivalent to
~
OUT2 of XFCH (bit 3).
,\
0 Reset when the CF input is inactive.
132 Serial/Parallel Card