Radio/Leased-line Modem

Adapts conventional voice radios for data operation Also supports leased-line & twisted-pair wiring 1200 & 2400 baud data throughput Protocol independent, including Modbus Data packetizing for improved error rejection Automatic message collision avoidance Does not require special software handshaking Built-in test tone generator for easy setup Audio monitor jack for system troubleshooting Closed-case configuration – no pots or jumpers! Compact: small footprint and light weight Rugged "bullet-proof" aluminum package Low power: 10 to 30Vdc, 0.3 watts maximum

The RMX-2400 is an easy-to-use data modem for voice radio as well as leased telephone line and twisted-pair wire operation. Two or more of these modems may be used to form a reliable data communications link between RTUs, industrial controllers and PCs for SCADA, telemetry and data acquisition applications.

The RMX-2400 is compatible with most any conventional voice radio that uses a push-to-talk switch. This allows voice channels to be used for data purposes without additional licensing and at a lower cost than specialized telemetry radios.

The RMX-2400 can also be used with leased telephone lines and twisted pair wiring, providing a reliable, transformer-isolated link that is free of ground loops and destructive electrical transients.

User Configuration (non-volatile):

Radio/Leased-line Data Rate	1200 & 2400 baud
Host (DCE) Data Rate	2400, 4800 & 9600 baud
Operating Mode	Half or Full Duplex (Half is standard)
Audio Input Level (radio)	10mVrms to 1.27Vrms
Audio Output Level (radio)	30mVrms to 1.27Vrms ( >1K ohm load )
Audio Input Level (leased-line)	10mVrms to 1.27Vrms
Audio Output Level (leased-line)	30mVrms to 1.27Vrms ( 600 ohm load )
Data Monitor Level (headphone)	0 to 250mVrms ( > 600ohm load )
Push-to-Talk Timing – Lead Delay	0 to 2.55 seconds, 10ms increments
Push-to-Talk Timing – Trail Delay	0 to 2.55 seconds, 10ms increments
Character Gap Timing (maximum)	0 to 2.55 seconds, 10ms increments
Carrier Detection	Internal or External (from radio)
Command Mode Timeout	1 to 254 minutes, 1 minute increments

Data Section:

Electrical Interface	RS-232C compatible (TX & RX only)
Connector	DB-9, female (DCE configuration)
Message buffer	232 bytes (maximum message length)
LED Status Indicators	TXD – Transmit Data RXD – Received Data TXEN – Transmit Enable (to key radio) CD – Carrier Detect ST – Status (configuration mode & internal errors)

Audio/Modem Sections:

Recommended Audio Bandwidth	2.0KHz @ 1200 baud, (-1 dB) 3.0KHz @ 2400 baud
Bit Error Rates @ 20 dB SNR	1.0 x 10-8 @ 1200/2400 baud
Bit Error Rates @ 12 dB SNR	2.5 x 10-4 @ 1200 baud, 1.5 x 10-3 @ 2400 baud
Test Tone	2400Hz, pulsed ON for 0.1 to 25.4 seconds
External Carrier Detect Input	Contact Closure to Ground, 10Kohm pull-up to 5Vdc
Push-to-Talk Interface	FET transistor switch to ground, 100Vdc, 300ma maximum
Connector	9-pin removable 2.5mm terminal block (mating connector supplied)

General:

Enclosure	Extruded aluminum
Operating Temp. Range	-40°C to +70°C
Humidity	0 to 95% non-condensing
Dimensions	33 x 88 x 88 mm 1.30 x 3.45 x 3.45 inches
Power	8 to 30Vdc, 0.3 watts maximum
Power Connector	9-pin removable terminal block, shared with audio in/out

Ordering Information

Model #	Description
94-1024	Radio & Leased-line Data Modem
90-0912	Wall Plug Power Supply for RMX-2400 (optional)

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