Page 1¶

ND 750 LIMITED DISTANCE MODEM¶

INTRODUCTION¶

The ND 750 is a low cost, high-performance modem intended for use over distances up to 10 km (6 miles). It meets EIA RS-232 and CCITT V24 specifications. The unit has full duplex capability, and accepts any transmission rate up to 9600 bps.

The transmission is performed by a three-state balanced current loop. This technique gives the ND 750 the capability to transmit one additional signal in each direction, so that the status of the lines and the terminals can be monitored.

The ND 750 can be used in local communication links between computers, CRT displays, typewriters, printers etc. It is an easy-to-use, small size and low cost unit.

  ____________      0-10 km      __________
 |            | <--------------> |          |
 |  ND117 or  | Rs 232 15 m     | ND 750   |
 |  ND252 or  |                 |          |
 |  ND271 or  |                 |          |
 |  ND281 or  |                 |          |
 |  ND272     |                 |          |
 |____________|                 |__________|
                                 |  Rs 232 1.2 m
                                 |/            
                              Printer        
                              ND 418 or
                              ND 427 or 
                              ND 232

FEATURES¶

Asynchronous transmission
Full duplex
0-9600 bps (any rate)
EIA RS-232/CCITT V24
2- or 4-wire
Opto-coupler isolation
Local links up to 10 km
Line and terminal monitoring
Easy to use
Easy to install
Small size
Low cost

SPECIFICATIONS¶

Feature	Description
Interface	According to EIA RS-232/CCITT V24
Transmission	Asynchronous, full duplex
Speed	Any rate from 0 to 9600 bps
Line	Simplex: One twisted pair
	Full duplex: Two twisted pairs

  750—A1—4000—1280

Page 2¶

Technical Specifications¶

General Specifications¶

Max. distance:
- 9600 bps ............ 0.9 km
- 4800 bps ............ 1.5 km
- 2400 bps ............ 3 km
- 1200 bps ............ 5 km
- 600 bps ............... 10 km

Transmission technique:
+/- 10 mA three-state balanced current loop

Isolation:
Opto-coupler

Isolation voltage:
1500 V

Power:
220 VAC +/- 10%, 40–60 Hz
Other supplies on request

Dimensions:
80 x 150 x 50 mm

Weight:
0.5 kg

Temperature range:
5–50°C

Humidity:
0–95% RH, non-condensing

DTE Connection (To DB25S Connector)¶

RS-232¶

Pin No.	Designation	Signal Name
1	AA	Protective ground
2	BA	Transmitted data
3	BB	Received data
4	CA	Request to send
5	CB	Clear to send
6	CC	Data set ready
7	AB	Signal ground
8	CF	Received line signal detector
20	CD	Data terminal ready
18	—	Data terminal busy

Transmission Line Connection (To ND 750 Screw Terminals)¶

flowchart LR
    A[ND 750] -->|1| B[ND 750]
    A -->|2| C[Transmitter]
    A -->|4| D[Shield (optional)]
    B -->|6| E[Transmitter]
    B -->|2| F[Receiver]
    B -->|4| G[Shield (optional)]

NOTE: If shield cable is used, just connect the shield at one end of the transmission line.

Indicators¶

Power On (red LED)
Carrier On (green LED)
On-board indicator: Transmitted data

Contact Information¶

Norway:
NORSK DATA A.S
Jerikoveien 20, Box 4 Lindeberg gård
OSLO 10
Tel. 02-90300, tik. 18661 nd no
Bergen: tel. 05-29560
Sandnes: tel. 045-66662

Denmark:
NORSK DATA ApS
Øverødvej 5
2840 HOLTE
Tel. 02-425055, Tik. 37725 nd dk

Sweden:
ND NORSK DATA AB
Kanalvägen 3, Box 2031
194 02 UPPLANDS VÄSBY
Tel. 0760-8050, tlx. 13528 nordata s
Gothenburg: tel. 031-299350
Malmö: tel. 040-70510

West Germany:
NORSK DATA DEUTSCHLAND GmbH
Abraham-Lincoln-Str. 30
6200 WIESBADEN
Tel. 06121-764220, Tik. 4186370 noda d

U.S.A.:
NORSK DATA N.A., Inc.
65, William Street
Wellesley, MASS. 02181
Tel. 0617-237.7945, Tik. 921740 norsk well

France:
NORSK DATA FRANCE
"Le Brevent", Avenue du Jura
01210 FERNEY-VOLTAIRE
Tel. 050-408576, Tik. 385653 nordata fernv
Paris: tel. 01-6023366, Tik. 201108 nd paris

England:
NORSK DATA Ltd.
NORB House, Pelican Lane, Newbury
BERKSHIRE RG13 1NU
Tel. 0663-31465, Tik. 849819 norsk g

Note: NORSK DATA reserves the right to change specifications at any time without given notice.