HP 82718A Expansion Pod Reference Manual page 92

Low-Level Modem Command Dictionary
being issued will be halted. VOICE mode is for voice communication where the modem is used as an
auto-dialer only. In VOICE mode, you can dial phone numbers using the
X (XMIT)
command. If the
modem was off-hook, it will remain off-hook.
Responses: none
x
(XMIT)
I
X [dial string]
Dials a number without call progress reporting after dialing. The X command is similar to the D (DIAL)
and R (REDIAL) commands in that it dials a
dial string.
However, that is all that X does. Unlike the
o
and R commands, it only reports three responses: BUSY if the line is busy, CONNECT if there is no busy
signal, and NO DIAL if there was no dial tone.
The X command simplifies the use of the modem as an auto-dialer in VOICE mode. If the D command is
used for auto-dialing, it will still report all its responses (except BAD ANS and NO ANS), even when they
are irrelevant to a voice connection. Using X eliminates almost all phone line monitoring before, during,
and after the dialing operation. The only exception is that an implied or explicit P in the
dial string
will check for a dial tone before dialing, and report NO DIAL if there is none.
The X command only works in VOICE mode and if the modem is off -hook. The simplest way to put the
modem in VOICE mode and take it off-hook is with the P (PICKUP) command. Consequently, a
common command string when using X is P, X followed by the
dial string,
as in the example.
Responses: 3
Z (ZAP)
t'1DDOUT
II
~·~z
II
t:CHF.:$
0::
1
:::::0
Clears the modem receive buffer. If the command string contains more than just the Z command, the
buffer will be cleared after all the other commands in the string have been executed and their responses
have been placed in the receive buffer. Once the buffer has been cleared, the normal response to any
completed command (OK or 4) is placed in the receive buffer. Consequently, Z does not leave the buffer
completely empty.
Also, the Z command does not clear the HP-7 5 buffer containing data saved by
t'10DOUT
(see
t'1ODOUT).
Any characters saved by
t"IODOUT
before Z is executed will still be returned by
t'10D Ttlt-.
Because of
this, and because of the appearance of the normal command response, the most effective method for
clearing the receive buffer is to use
t'10D
I t·l$ until it returns a null string .
• The response to the Z command is almost the same response that is reported when the modem is
turned on-%OK without a leading or trailing
~R :~r
for the long response, or
%4:;1
without a leading
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