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 |