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Software Usage and Examples
P W 9 W 1(800)555-1212
ll
Lwait 5, to attain access, then force tone dialing
Dial access code
Wait 5 s, then force tone dialing
verride implied P, wait 4.5 s for dial tone, report
NO
DIAL if none, then force adaptive dialing
The penalty of this approach is that it adds 4.5 s before the access code will be dialed.
PULSE DIAL STRING. A dial string that dials a phone number using only pulses starts with PI (the Pis
so
NO
DIAL will be reported) and has WI between the access codes:
P I 9 W I 1(800)555-1212
ll
LForce pul,e dialing
Wait 5 s to attain access, then force tone dialing
Dial access code
Force pulse dialing
verride implied P, wait 4.5 s for dial tone, report
NO
DIAL if none, then force adaptive dialing
The PI could actually be simplified to
1.
This uses the implied P instead of the explicit P, since the I does
not override the implied P the way W or P do. The only reason to use the implied P is that it is
1.
5 s
shorter than the P, and thus reduces the total dial time by that amount.
TOTAL DIALING TIME. The total time to tone dial PW9W1 (800) 555-1212 is 16.3 s. The total time
to pulse dial PI 9WI 1 (800) 555 -1 21 2 is 25 s. By using the implied P, these would be reduced to 14. 8 and
23.5 s. These times are calculated using worst-case times for the operation of the dialer in the modem, as
follows:
Tone Dialing
Tone duration
Intertone delay
65-75 ms
65-75 ms
Pulse Dialing
Pulse rate
Interdigit delay
10-11 pulse/s
700-800 ms
Using a Telephone as a Line Monitor
You can connect a telephone to the second modular jack of the HP 82 718A and use it as a line monitor to
listen to dialing and data communication activity. If the modem must dial using pulses, the user of the
program cannot listen to a phone plugged into the second modular jack until after the dialing has been
completed. This is because of the way pulse dialing works.
Pulse dialing actually puts the modem back on -hook briefly during every pulse of the digit being dialed.
r
~,
For example, if a 7 is pulse dialed, seven pulses will be heard, and the modem goes on-hook seven times. A •
telephone connected to the second modular jack is connected in parallel with the modem.
If the
telephone is off-hook because the user is listening to it, the modem cannot go on-hook while pulse dialing
38
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