TEA7092 ST Microelectronics, Inc., TEA7092 Datasheet - Page 18

• Manufacturer Part Number: TEA7092
• Description: Telephone Analog Front End
• Manufacturer: ST Microelectronics, Inc.

TEA7092
MICROCONTROLLER INTERFACE (continued)
RING Mode
- Ring frequency generator :
- Ring indicator input (RI/VI) :
Ring Melody Control
The melody can be checked in off-hook by sending
the following sequence of codes :
- LOUDSPEAKER LEVEL : 0100XXX.
- Fi data : 000XXXX.
- DIVIDER data : 1XXXXXX.
- RING MELODY CONTROL : 0110011.
To change the melody or the level, only loud-
speaker level, Fi data and n divider data have to be
sent. To stop the ring melody, a speech code
0010000 is sent.
Figure 9 : Time Diagram of Transfer Request
18/24
In ring mode, to generate the ring melody in the
loudspeaker, the following sequence is sent :
To change the ring frequency only Fi data and
divider data are sent again.
In ring mode the TEA7092 generates a high logic
level on pin RI/VI, as soon as the voltage on pin
RSU is higher than 19V, and the voltage on pin
V
pin V
goes high.
RI/VI
RI/VI
RMC
LOUDSPEAKER LEVEL : 0100XXX.
Fi DATA : 000XXXX.
DIVIDER DATA : 1XXXXXX.
GROUP LISTENING CODE : 0110001.
RING START : 0010001.
SPEECH : 0010000 (To stop the ring mode
when off-hook is detected, PON = 1).
RMC
Transfert Request
Flip-Flop Operating
is higher than 2.6V. When the voltage on
t0
t0
is higher than 2.6V, the RESET output
Line Current Memorization Activated
Line Current Memorization Activated
µP Send the Code (0011010)
µP Send the Code (0011010)
Error Beep
Error beep could be used to signalize wrong opera-
tions (memory empty, re-dial empty, store too many
digits in a memory...) or for other procedures, like
melody. To generate the error beep, the following
sequence of codes is sent :
- Fi data : 000XXXX.
- DIVIDER data : 1XXXXXX.
- ERROR BEEP code : 0011100.
To stop the error beep a speech code 0010000 is
sent. The error beep is a square wave sent on the
earphone, if it is requested to send it also in the
loudspeaker, the Group listening code should also
be sent.
Line Current Variation Detection
The TEA7092 has a line current variation detector.
This feature memorizes the line current value.
When the transfer request code is sent, and if a the
current inside the TEA7092 decreases of 15% or
more of the line current value, due for example to
a telephone set off-hooked in parallel on the same
line, the output RI/VI goes HIGH to prevent the
associated microcontroller. Oscillator should be
ON, and it is preferable to mute the transmit and
receive paths to avoid current variation due to ac
signals.
- TRANSFER REQUEST : 0011010.
If the Transfer request code is sent again, the
current memorization is disabled.
Line Current Memorization Cancelled
Line Current Variation
(if > 15% of IL)