as2525 austriamicrosystems, as2525 Datasheet - Page 13

• Manufacturer Part Number: as2525
• Description: Single Chip Handsfree Phone Cmos Integrated Circuit
• Manufacturer: austriamicrosystems

Datasheet AS2525
Loudhearing
A loudhearing mode can be enabled/disabled through the
set-up programming.
Table 19: Loudhearing mode selection
Headset mode
Head set mode is selected by connecting pin "HEAD" to
VDD and enabling the head function by service code
programming (see also Table 3: Parameter settings).
Table 20: Headset Tx gain setting
Table 21: Headset Rx gain setting
Revision 2.1
Digit
Key
Key
[PG] + [0] + (Password) + [#] + [7] + (digit) + [PG
[0]
[1]
(x)
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
(x)
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[PG] + [0] + (Password) + [0] + [7] + (x) + [PG]
[PG] + [0] + (Password) + [0] + [8] + (x) + [PG]
Loudhearing
Enabled (LH + HF provided)
Disabled (only HF is provided)
Rx Gain (dB)
Tx Gain (dB)
M1/2 to LS
LS to RO
30
31
32
33
34
35
36
37
-6
-5
-4
-3
-2
-1
0
1
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
Key
Key
(x)
(x)
[8]
[9]
[8]
[9]
Tx Gain (dB)
Rx Gain (dB)
M1/2 to LS
LS to RO
38
39
40
41
42
43
44
45
2
3
4
5
6
7
8
9
]
If this mode is entered both hook inputs HS and HF act as
electronic off-hook for handset operation. The gain in
transmit and receive can be programmed by service code
programming. The pin "HEAD" is only scanned once after
off-hook and any change on this pin during one session will
be ignored.
Ring Frequency Detection
The ring frequency detector assures that only signals with
a frequency between 13 Hz and 70 Hz are regarded as
valid ring signals.
When a valid ring signal is present for 100 ms
continuously, the melody generator is activated and
remains active as long as the ring signal is present.
Once the melody generator has been started, the ring
signal is continuously monitored and the melody generator
is instantly turned on or off according to the momentary
presence of a valid or invalid ring signal respectively (until
next POR or off-hook).
DC/DC converter
When a valid ring signal is detected, the dc/dc converter is
started.
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