MT88L70

Data Sheet

4

Zarlink Semiconductor Inc.

the steering time constants externally, allows the designer to tailor performance to meet a wide variety of system

requirements.

Table 1 - Functional Decode Table

L=LOGIC LOW, H=LOGIC HIGH, Z=HIGH IMPEDANCE

X = DON‘T CARE

Guard Time Adjustment

In many situations not requiring selection of tone duration and interdigital pause, the simple steering circuit shown

in Figure 3 is applicable. Component values are chosen according to the formula:

the receiver. A value for C of 0.1

µF is recommended for most applications, leaving R to be selected by the

designer.

Digit

TOE

INH

ESt

ANY

L

X

H

ZZZZ

1

H

X

H

0001

2

H

X

H

0010

3

H

X

H

0011

4

H

X

H

0100

5

H

X

H

0101

6

H

X

H

0110

7

H

X

H

0111

8

H

X

H

1000

9

H

X

H

1001

0

H

X

H

1010

*

H

X

H

1011

#

H

X

H

1100

A

H

L

H

1101

B

H

L

H

1110

C

H

L

H

1111

D

H

L

H

0000

AH

H

L

undetected, the output code

will remain the same as the

previous detected code

BH

H

L

CH

H

L

DH

H

L