as2574b austriamicrosystems, as2574b Datasheet - Page 3

• Manufacturer Part Number: as2574b
• Description: 20 Number One Touch Dialler With Serial Bus For Display Driver
• Manufacturer: austriamicrosystems

Data Sheet
Pin Description Continued
Keyboard Layout
Rev. 1
The keyboard is arranged in a 5 x 6 contact matrix with single pole single throw
contacts (SPST).
Keyboard resistance: Ron < 5 k ; Roff > 5 M .
Pin #
28
24
25
26
27
1
2
3
4
5
L S
1
1
*
4
7
Pin Node
TONE
Vdd
Vss
HS
TB
LNR
2
2
5
8
0
Description
Hook switch input; active high with internal pull-down resistor. Debounce 25 ms.
Negative terminal of power supply.
Tone burst output:
MF tone output.
An on chip reference voltage provides tone levels independent of the
supply voltage.
A dc path from TONE output is needed to accommodate an external voltage
divider for setting the appropriate tone level.
Frequencies:
Positive terminal of power supply
M9
3
3
6
9
#
LS high
MT high
MT+LS high
Frequency (Hz)
COLUMN
1209
1336
1477
1633
697
770
852
941
RECALL
ENTER
MUTE
MEM
2ND
4
3
80 ms burst, 2 sec pause
80 ms burst, 8 sec pause
80 ms burst, 2 sec pause
Key Matrix (Hz)
M10
M1
M2
M3
M4
see p. 7
5
row 1
row 2
row 3
row 4
col. 1
col. 2
col. 3
M5
M6
M7
M8
6
Error (%)
In off-hook state all keys are
enabled (CD = high)
0.7%
Only in speech mode
Enabled only
when off-hook
Enabled also
when ACP is
active (diode 5
inserted)
Enabled when
CD = high
AS2574B
Jan. 1995