TELEBYTE TECHNOLOGY, INC.

MODEL 420

Modem Type

Data (synchronous)

Maximum Data Rate

128Kbps

Data Bus

External

Data Modulation Protocol

Proprietary

CONNECTIONS

Purpose

Location

Purpose

Location

DC power

CN1

Receive

CN4

RS-232/422

CN2

Transmit

CN5

Ground

CN3

   

CARRIER ON

Setting

SW2/C

» Always on

On

RTS high

Off

GROUND

Setting

JP1

» Frame and signal ground connected

Pins 1 & 2 closed

Frame and signal ground separate

Pins 3 & 4 closed

IMPEDANCE

Setting

JP2

» 135 Ohms(low)

Pins 1 & 4 closed

High

Pins 3 & 4 closed

LINE SPEED

Speed

SW1/A

SW1/B

SW1/C

SW1/D

SW1/E

SW1/F

32Kbps

Up

Down

Down

Down

Down

Down

48Kbps

Down

Up

Down

Down

Down

Down

56Kbps

Down

Down

Up

Down

Down

Down

» 64Kbps

Down

Down

Down

Up

Down

Down

72Kbps

Down

Down

Down

Down

Up

Down

128Kbps

Down

Down

Down

Down

Down

Up

RECEIVE CLOCK

Setting

SW/H

» Disabled

Down

Enabled

Up

RTS/CTS DELAY

Setting

SW2/A

SW2/B

» Disabled

Off

Off

7ms

On

Off

60ms

Off

On

TRANSMIT CLOCK SOURCE

Setting

SW1/G

» Internal

Down

External

Up

FACTORY CONFIGURED SETTINGS

Jumper

Setting

SW2/D

Not used

DIAGNOSTIC LED(S)

LED

Color

Status

Condition

PWR

Red

On

Power is on

PWR

Red

Off

Power is off

TD

Red

On

Modem is transmitting data

TD

Red

Off

Modem is not transmitting data

RD

Red

On

Modem is receiving data

RD

Red

Off

Modem is not receiving data

RTS

Red

On

RTS signal is high

RTS

Red

Off

RTS signal is low

DCD

Red

On

Carrier signal detected

DCD

Red

Off

Carrier signal not detected

TM

Red

On

Modem is in test mode

TM

Red

Off

Modem is in test mode