FSK Short-Haul Modem

Perfect for your industrial applications, this modem is highly immune to noise and interference.

SHM-FSK transmits farther than most short haul modems up to 9.5 miles.

Short-Haul Modem-FSK

Ideal for private lines or any dedicated wire pair

Versatile, reliable and durable- designed especially for industrial applications

Exceptional immunity to EMI/RFI

Easily interfaces with PLCs, RTUs and PCs

Supports multidrop polling applications and point-to-point installations

Factory or field configured for your application ensuring trouble-free installation

Protocol and baud rate transparent

Optional long range version available (up to 8 miles)

MDL500 FSK Wire Modem
MDL500 FSK Wire Modem for data over private lines or any dedicated wire pair.
The MDL500 Frequency Shift Key (FSK) series offers maximum versatility and reliability. With simplex, half duplex and full duplex capability, the MDL500 FSK series provides unsurpassed flexibility for private lines or any dedicated wire pair (twisted or untwisted, shielded or unshielded) industrial application. The MDL500 incorporates a special filter section in the FSK receiver. This filter eliminates out-of-band electromagnetic interference (EMI). As a result, the MDL500 can utilize shielded pair, most untwisted and unshielded wires with error-free operation.

When the MDL500 FSK modem is configured for multi-point, multi-drop operation, the carrier is controlled by the RTS line of the connected addressable device. The turnaround time (RTS to send delay time) is only 20 milliseconds, permitting high system data throughput. The MDL500 has unique circuitry that stabilizes the received carrier rapidly and eliminates any false triggering by the Master’s receiver when any Remote’s transmitter is turned on or off.

The MDL500 FSK series is factory pre-configured for simple installation. This series range is up to eight miles, based on 24-gauge wire. Larger wire gauges can increase range.

The MDL500 FSK is ideal for applications where only power lines connect the locations requiring data transfer. It can be used to communicate data over sliding contacts with high reliability, including slip rings and rolling wheels, as well as shoes on conductor bars.

DOVE Data Over Voice Encoder
"The DOVE" for data over PBX phone lines
The Data Over Voice Encoder (DOVE)/MDL500 incorporates special filters which permit the transmission of data over operating facility PBX telephone lines simultaneously–with normal voice communications and no interference. The DOVE/MDL500 provides optimal data communications throughout a facility by superimposing the data on in-place wiring–thereby eliminating the need for costly data cable installation.

The DOVE/MDL500 can also be used to transmit digital data over in-service current loop instrumentation lines. This is the preferred method of adding data communication capability using existing wires without disturbing the wires’ initial function.

DOVE Data Over Voice Encoder
Line Carrier Modem for data over power lines

The LCM/MDL500 with high voltage interface and powerline isolators permits full duplex data transmission over in-use power lines at up to 9600 baud. Line voltage and current can be up to 600 volts and 200 amps. Data-Linc Group’s PLI500 Power Line Isolators block outside noise produced by the power grid from interfering with data reliability.


Industrial Applications
The MDL500 is ideal for industrial automation systems requiring control of:

    Stacker cranes
    Material handling equipment
    Rotating molds or any mobile robotic equipment
    Hydroelectric generators
    Railroad signaling controls
    Mine safety monitoring
    Flow meter pulse train transmission
    Various manufacturing applications.

MDL500 FSK Series Specifications
Data Format
Optional. RS422/485

Two-wire, full duplex or half duplex controlled carrier, asynchronous data
Four-wire, long range version available

Point-to-point or multi-drop option

Data Transmission Speed
Up to 9600 baud

Frequency shift key (FSK); carrier signal transformer and capacitively isolated

DTE/DCE jumper selectable; Female DB-25 connector for RS232C; two position pluggable terminal block for carrier; 2.5 mm x 5.5 mm barrel jack (center positive) for 24 VDC power

Two-conductor wire.
Up to 20,000 feet (6.1 km)
Four-wire, long-range unit. Up to 40,000 feet (12.2 km)

21 to 28 VDC or 120 VAC (wall transformer provided)

Operating Environment
Temperature Range.
32o to 140oF (0o to +60oC)
Humidity. 0 to 95%, non-condensing

16-gauge steel with mounting flanges
Dimensions. See drawing

3.56 lbs (1.62 kg)


ARC Electronics
301-924-7400 EXT 25

Home Page