uba2051t NXP Semiconductors, uba2051t Datasheet - Page 26

• Manufacturer Part Number: uba2051t
• Description: Uba2050 A ; Uba2051 A;c One-chip Telephone Ics With Speech, Dialler And Ringer Functions
• Manufacturer: NXP Semiconductors

Philips Semiconductors
K
A keytone with a frequency f
pressed resulting in the expected action, digit keys in tone dialling mode excepted.
Pin KT is a push-pull output and is set LOW when V
Key sequences
The behaviour of the UBA205xx can be represented as
a State Transition Diagram (STD).
The STD contains the states (rectangles in Fig.28) and
state transitions (arrows) of the set. The upper arrow in the
figure pointing to the standby state means that the set is
initially in the standby state. When, for instance, an
incoming call is detected, the set enters the ringer state,
waiting for end of a ringer signal or off-hook. If the set goes
off-hook, the UBA205xx enters the on-line state.
The UBA205xx has 3 basic states:
Each state with its own functional requirements is
described in the following sections.
S
In the standby state the UBA205xx is inactive. The current
drawn is for memory retention; the loads on the
inputs/outputs of the dialler have influence on the retention
current.
2000 May 19
handbook, full pagewidth
EY TONE
TANDBY STATE
Standby state
Ringer state
On-line state.
One-chip telephone ICs with speech,
dialler and ringer functions
t
f
kt
kt
= keytone time.
= keytone frequency.
(
PIN
KT)
keytone
kt
= 597 Hz and a duration t
f kt
t kt
Fig.27 Keytones via KT output.
DD
< V
kt
= 30 ms (see Fig.27) is generated each time a valid key is
26
POR
The UBA205xx leaves the standby state if:
The UBA205xx returns to the standby state if:
R
If the set is in standby state, a ringer signal can be received
from the line. After evaluating the incoming ringer signal
(and the ringer signal is valid), the UBA205xx starts a
melody via the MDY/TONE output and ringer hardware;
this melody is stopped when the ringer signal is no longer
valid. After going off-hook, the ringer signal stops and the
set is in the conversation (on-line) state.
While ringing, the melody can be changed according to
Table 8 and the volume according to Table 9.
As long as memory retention conditions are fulfilled,
melody and volume are stored.
.
INGER STATE
The set goes off-hook (lift handset)
A ringer signal is available on the line.
The set goes on-hook (handset on-hook)
A line-break occurs with a duration greater than t
The ringer signal becomes invalid.
f kt
UBA2050(A); UBA2051(A;C)
t kt
MGM344
Product specification
RD