A
-
2
A
P
P
E
N
D
I
X
A:
M
O
D
E
M
S
P
E
C
I
F
I
C
A
T
I
O
N
A
N
D
I
N
T
E
R
F
A
C
E
P
I
N
A
S
S
I
G
N
M
E
N
T
S

D

ata Input

Serial binary. Complies with CCITT V.28.

A

ccepts levels

±3

volts to

±2

5

volts. (+)= space (-)= mark. Single wire ground return. 3000 to 7000

ohms load.

Data Output

Serial binary. Complies with CCITT V.28

±1

2 volts nominal. Output

impedance 300 ohms.

Synchronization

RTS/CTS delay dependent on modulation format.

Equalizer

Automatic adaptive

equalizer.

Error correction

V.42 LAPM and MNP4.

Data compression

V.42bis and MNP5.

Autodial - Autoanswer

Method

Pulse dial. 10 pps rate. Make period 33 msec. Break period 67 ms

ec

(UK

version). Interdigit period 800msec. Tone dial. On time 85 msec. ID time

85 msec. Duty cycle 50%.

Line Interface

600 ohm impedance. Bell tinkle suppression provided. Old and new

dial tone detection. Secondary dial tone detection for PABX use.

Progress tones and answer tone detection.