Omega Products LDM85 User Manual

Model LDM85

Baud Rate Range TTL 0-5M, 0-2.5M NRZ Baud Rate Range RS-232 0-100K

Distance (miles) Up to 1.2 depending on cable Distance (km) Up to 2 depending on cable Channel Lines

(1)

TD, RD, TTL TD, TTL RD

Control Lines

(1)

RTS, CTS, DSR, DTR, RLSD

Modes Asynchronous 2-fiber full duplex,

1-fiber simplex

Optical Transmitter 820 nm wavelength -11.5dBm typical output from

1 m cable, -16dBm minimum output (-40°C to +85°C)

Transmitter Numerical 0.49

Aperture

Transmitter Optical Port 290 µm

Diameter

Optical Receiver -25dBm to -12dBm dynamic range for logic 1,

-24dBm minimum input logic 1 (-40°C to +85°C),

-40dBm maximum input logic 0

J-19

⻬ Data Rates to 5M Baud ⻬ RS-232, RS-422, TTL

System Interfaces

⻬ Multipoint Capability ⻬ LED Indicators ⻬ DCE/DTE Switch ⻬ Small Size ⻬ SMA- or ST-Compatible

Optic Connectors

⻬ 120/220 Vac, +5Vdc or

8 to 20 Vac/dc Power

⻬ Connector

Cables Available

Specifications

Notes: (1) TD = Transmit Data, RD = Receive Data, TTL TD and TTL RD are DCE referenced TTL signals, RTS = Request To Send, CTS = Clear To Send. DTR = Data Terminal Ready, DSR = Data Set Ready, RLSD = Received Line Signal Detect.

299

Basic Unit

The LDM85 is a small, inexpensive fiber optic transmitter/receiver. It features a complete RS-232 port as well as high speed TTL/RS-422/ RS-423 data transmit and receive. It is capable of data rates from DC to 5M baud. A pair of these units allows most RS-232C cable links to be replaced and extended with a duplex fiber optic cable. The normal 50-foot RS-232 limit may be extended to 1.2 miles (2 km).

Fiber optic data communications provide complete EMI/RFI rejection, isolation, elimination of ground loops, and reduced error rates.

Data security is enhanced by almost nonexistent electromagnetic emissions. A unique multipoint capability allows local area networks to be formed with the isolation and data security of a fiber optic data highway.

The LDM85 is packaged in a rugged aluminum enclosure small enough to mount on the back panel of typical computer equipment, saving valuable desk and floor space. The RS-232 connection is through male or female EIA 25-pin connectors.

The fiber optic connection is either through SMA (905) or ST connectors. Additional features include a TD/RD reversing switch for connection to DTE (Data Terminal Equipment) or DCE (Data Communication Equipment) ports, three diagnostic LED indicators, and locally connected handshake lines.

The TTL port combined with the RS-232 port may be interfaced to RS-422/423 ports.

Recommended Cables

The LDM85 optical transmitter is optimized for launching power into fiber sizes 85/125, 100/140, and 200µm plastic coated silica (PCS).

Extended Warranty

Program

LDM85 Series

Fiber Optic Modem

SERIAL I/O

Model LDM85

Receiver Equivalent 0.50

Numerical Aperture

Receiver Optical Port 400 µm

Diameter Power Budget 8dB (-40°C to +85°C), 10dB (-20°C to +55°C) Optical Connectors SMA (905), ST DCE/DTE Switch 1 Diagnostic LEDs 3 Power:

AC operation

(2)

120 Vac or 220 Vac (3W wall transformer) 10 Vac to 20 Vac (3W transformer rating)

DC operation +8 Vdc to +24 Vdc @ 130 mA

+5 Vdc ±0.25 Vdc @ 130 mA

Operating Environment -40°C to +85°C, 0 to 95% relative humidity

non-condensing

Dimensions 3.75" x 2.1" x 1" (95.3 x 53.3 x 25.4 mm) Weight 3.7 oz (105 g) max

AC Transformer 11.0 oz (311.8 g)

MTBF >120,000 hrs

J-20

#1 #2

#25

#26

#1 #3

Repeater Pairs*

1.2 mi (2 km)

Extended Multipoint Loop

Multipoint Loop

Long Distance Communications

1.2 mi (2 km)

0.6 mi (1 km)

0.6 mi

(1 km)

Host

1.2 mi (2 km)

Repeater*

DCE

DTE

LDM85

ACT

2.085 (53.0)

1.868 (47.4)

0.216 (5.5)

1.968 (50.0)

0.116 (3.0)

1.00 (25.4)

0.497 (12.6)

0.252 (6.4)

0.573 (14.6)

3.38

(85.9)

1.491 (37.9)

0.566 (14.4)

0.45

(11.4)

Dimensions: Inches (mm)

0.315 (8.0)

0.80

(20.3)

LDM85 LDM85

Due to a lensed optical system, receiver response does not vary with fiber size.

Multipoint Operation

Local area networks are easily implemented with LDM85. When a talker unit raises Request To Send (RTS), its data is communicated to all other devices on a common loop.

Data returns to the sending unit, verifying physical integrity of the loop. Alternately, if pin 16 is strapped to pin 17, echo will be inhibited. Units may be ordered with this connection made internally.

For multipoint installations, it is important that power be applied to all LDM85s. For small networks it will likely be acceptable to power each unit from a local source. Larger networks may benefit from routing a common low voltage power bus along with the fiber optic cable. An AC bus with isolation transformers at each unit will preserve system resistance to electrical disturbances. The wide low voltage AC and DC tolerance makes voltage drop on this bus easily accommodated.

Power

AC or DC power may be applied to the screw terminals or to pin 9 of the 25-pin connector. Alternatively the unit may be powered by +5 Vdc on pin 18.

To Order

(Specify Model Number)

RS-232 Power

Model No. Price Connector Field Connector Source

LDM85-P $285 25 Pin male SMA(905) fiber optic connector 5 Vdc LDM85-S 299 25 Pin female SMA(905) fiber optic connector 5 Vdc LDM85-PT 319 25 Pin male SMA(905) fiber optic connector Transformer LDM85-ST 319 25 Pin female SMA(905) fiber optic connector Transformer LDM85-P-025 299 25 Pin male ST fiber optic connector 5 Vdc LDM85-S-025 299 25 Pin female ST fiber optic connector 5 Vdc LDM85-PT-025 319 25 Pin male ST fiber optic connector Transformer LDM85-ST-025 319 25 Pin female ST fiber optic connector Transformer

Includes operator’s manual. Transformer powered units also include 120 Vac wall mount transformer. OMEGACARESMextended warranty is available for models shown on this page. Ask your sales representative for full details when placing order.

Ordering Example: LDM85-ST converter, OMEGACARESM1year warranty for LDM85-ST (adds 1 year to standard 1 year warranty), $319 + 31 = $350.