![](http://datasheet.mmic.net.cn/330000/M-985-01P_datasheet_16431606/M-985-01P_4.png)
Truth Table
Signal Present (fo)
350 Hz
400 Hz (Note 1)
425 Hz
440 Hz
480 Hz
620 Hz (Note 2)
950 Hz
1400 Hz
1800 Hz
350 & 440 Hz
350 & 480 Hz
350 & 620 Hz (Note 2)
440 & 480 Hz
440 & 620 Hz (Note 2)
480 & 620 Hz (Note 2)
Invalid Tone Combination
Other (no detect)
Any
Mode
X
0
X
X
X
1
X
X
X
X
X
1/open
X
X
X
X
X
X
OUT 1
1
0
X
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
OUT 2
0
1
X
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
OUT 3
0
0
X
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
OUT 4
0
0
X
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
D425
X
X
1
X
X
X
X
X
X
X
X
X
X
X
X
X
0
0
Strobe
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
PD
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
OE
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EN
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
X
Pin Functions
Pin
OUT 1
OUT 2
OUT 3
OUT 4
D425
EN
OE
SIGIN
STROBE
VDD
VREF
V
SS
X358
XIN
XOUT
Function
Active high tri-state output, per Truth Table.
Active high tri-state output, per Truth Table.
Active high tri-state output, per Truth Table
Active high tri-state output, per Truth Table
Active high tri-state output, indicates 425 Hz detection.
Active high enabled, when low drives STROBE low.
Active high input. When low tri-states OUT n pins.
Analog signal input (internally capacitive coupled).
Active high output, indicates valid OUT n or D425
Most positive power supply input pin.
Internally generated mid-power supply voltage (output)
Most negative power supply input pin.
Buffered oscillator output (3.58 MHz).
Crystal oscillator or digital clock input.
Crystal oscillator output. Used only with a crystal. Use
X358 when clock output signal is required.
XRANGE Active low input. Adds 10 dB of gain to input stage.
MODE
Selects 400/620 Hz detector frequency, 400 Hz when
connected to V
SS
, 620 Hz when open.
PD
Power down operation, logic high inhibits internal
clock. Internal pulldown resistor.
MODE2
Tie high (V
) for normal operation. Tie low or leave
open to emulate M-982 operation.
www.clare.com
4
M-985-01
Rev. 1
For example, dial tones shown in absolute Maximum
Ratings Table on page 3, are usually “on” continuously
and last until the first dial digit is received by the switch-
ing system. Line Busy, on the other hand, is turned off
and on at a rate of 1 Hz with a 50% duty cycle, or an
interruption rate of 60 times per minute (60 IPM). The
tones can be distinguished in this way. It should be
noted that while such techniques will usually be effec-
tive, there are some circumstances in which the M-985-
01 cannot be accurately used. Examples include
situations where ringback tone may be short or not
even encountered. Ringback may be provided at ring-
ing voltage frequency (20 or 30 Hz) with some harmon-
ics and may not fall in the detect range, and speech or
other strong noise may obscure tones making cadence
measurement difficult.
Standards exist and should be consulted for your par-
ticular application. In North America AT&Ts “Notes on
the Network” or EIA’s RS-464 PBX standard should be
reviewed.
In Europe tone plans may vary with locale, in which
case the CEPT administration in each country must
be consulted. Outside these areas, national PTT
organizations can provide information on the systems
within their borders.