23-07-2012, 10:47 AM
DTMF Format
[attachment=28433]
DTMF Explained
DTM F stands for Dual Tone - Multi Frequency and it is the basis for your telephone
system. DTM F is actually the generic term for Touch-Tone (touch-tone is a registered
trademark of ATT). Your touch-tone® phone is technically a DTM F generator that
produces DTM F tones as you press the buttons.
How does it wok?
When you press the buttons on the keypad, a connection is made that generates two
tones at the same time. A "Row" tone and a "Column" tone. These two tones identify the
key you pressed to any equipment you are controlling. If the keypad is on your phone,
the telephone company's "Central Office" equipment knows what numbers you are
dialing by these tones, and will switch your call accordingly. If you are using a DTM F
keypad to remotely control equipment, the tones can identify what unit you want to
control, as well as which unique function you want it to perform.
Mannal vs Automatic Dtmf Encoders.
To send the digits quickly (40/40) you need to be using an automated encoder since you
could not press each button by hand that fast. An automated encoder is also called a
"Store and Forward" encoder. You "Store" the Dtmf code into the device when you
program it, then "Forward" it to send the entire Dtmf code as one complete Dtmf string
of numbers and characters.
Store and forward encoders can be
a programmable microphone or twoway
radio, a stand-alone encoder
such as the ENC-3300, or part of a
large law enforcement dispatch
console. In the end they all perform
the same function of sending out
Dtmf digits and characters.
If you are sending each Dtmf digit by
pressing each button individually,
then you are sending the code "M anually", rather than
"Automatically" with a store and forward encoder.
[attachment=28433]
DTMF Explained
DTM F stands for Dual Tone - Multi Frequency and it is the basis for your telephone
system. DTM F is actually the generic term for Touch-Tone (touch-tone is a registered
trademark of ATT). Your touch-tone® phone is technically a DTM F generator that
produces DTM F tones as you press the buttons.
How does it wok?
When you press the buttons on the keypad, a connection is made that generates two
tones at the same time. A "Row" tone and a "Column" tone. These two tones identify the
key you pressed to any equipment you are controlling. If the keypad is on your phone,
the telephone company's "Central Office" equipment knows what numbers you are
dialing by these tones, and will switch your call accordingly. If you are using a DTM F
keypad to remotely control equipment, the tones can identify what unit you want to
control, as well as which unique function you want it to perform.
Mannal vs Automatic Dtmf Encoders.
To send the digits quickly (40/40) you need to be using an automated encoder since you
could not press each button by hand that fast. An automated encoder is also called a
"Store and Forward" encoder. You "Store" the Dtmf code into the device when you
program it, then "Forward" it to send the entire Dtmf code as one complete Dtmf string
of numbers and characters.
Store and forward encoders can be
a programmable microphone or twoway
radio, a stand-alone encoder
such as the ENC-3300, or part of a
large law enforcement dispatch
console. In the end they all perform
the same function of sending out
Dtmf digits and characters.
If you are sending each Dtmf digit by
pressing each button individually,
then you are sending the code "M anually", rather than
"Automatically" with a store and forward encoder.