AS2540 datasheet(9/18 Pages) AMSCO

9 / 18 page

Data Sheet AS2540

austriamicrosystems

Revision 3.1

Page 9 of 18

The MF output levels are set to -4/-6dB which should allow

efficient backup dialling under all line conditions. The

TONE/PAUSE ratio is 90ms/90ms. The preemphasis

between low group and high group frequencies is t.m.

2.6dB.

FLASH timing

CPU can control the DPn pin and the MASK-mode of

AS2540 via serial interface.

Tone Ringer

Ring frequency discrimination

The ring frequency discrimination assures that only signals

with a frequency between 13Hz and 70Hz are regarded as

valid ring signals.

When a valid ring signal is present for 102ms continuously,

the ring melody generator is activated and remains active

as long as a valid ring signal is present.

Once the ring melody generator has started, the ring signal

is continuously monitored and the ring melody generator is

instantly turned off according to the momentary presence

of a valid or invalid ring signal until next off-hook.

Toner ringer melody

The 3 basic melody frequencies are:

F1=880Hz

F2=1067Hz

F3=1333Hz

The repetition rate is set to 4 which means that the

sequence of F1, F2, F3, F1, F2, F3 is repeated 4 times

within a second.

Keyboard connections

MODE

Double contacts under keys 0-9*#: One contact is

connected to AS2540, the other one to CPU.

AS2540 Datasheet(PDF) 9 Page - ams AG