RS-422, RS-485 Fiber Optic Modem

TC1520 fiber optic modem supports RS-422 and 2-wire or 4-wire RS-485 interfaces. 
It transmits asynchronous data at speeds up to 500 Kbps.

RS-422, RS-485 Fiber Optic Modem

(Model TC1520)

  • Async Data Rates Up to 500 Kbps 
  • RS-422, 2 or 4-wire RS-485
  • Detachable Terminal Block Connectors
  • Distances up to 20km
  • Multimode or Single Mode (850/1300/1550nm)
  • Six Diagnostic LEDs
  • Sturdy Compact Metal Case
  • Regular and Wallmount Base
  • High Temperature (-20C to 70C) Version Optional

(Wallmount Base Unit Shown)


The TC1520 RS-422/RS-485 Asynchronous Fiber Optic Modem are often used to link various process control systems in manufacturing plants, refineries, etc. It is also used to connect Remote Terminal Units to SCADA hosts or controllers in Utility environments.

The TC1520 work well in harsh environments because of their fiber optic benefits. This results in a simple and low cost solution to electrical/radio frequency interference and ground loop problems. Data security is also assured because fiber optic cable is virtually impossible to tap without detection.



Versatile and competitively priced, the TC1520 fiber optic modem supports RS-422 and 2-wire or 4-wire RS-485 interfaces.  It transmits asynchronous data at speeds up to 500 Kbps.*

Because the TC1520 can be multi-dropped on the electrical side (RS-485), it is ideal for poll and response applications such as SCADA and Process Control.  It will support one Remote Terminal Unit via the RS-422 interface.

Six visual indicators are provided for troubleshooting: Power, RS-485, Driver Mode, Receive Data, Transmit Data, Optic Sync.  Four DIP switches are provided for RS-485 Transition Time and Termination Resistor settings.

The TC1520 is compatible with all popular types and sizes of multimode (850nm/1300nm) or single mode (1300/1550nm) fiber optic cable.  Fiber optic connectors are ST or FC.  The electrical connectors are terminal blocks.  Power is 12VDC or 115/230VAC with an external power cube.  An extreme temperature version (-20C to 70C), Model TC1520T, is also available.

*Contact factory for higher requirements


Technical Specifications    

Data Rates
Async  up to 500 Kbps
Transmitter LED, ELED
Receiver PIN Diode
Wavelength 850nm, 1300nm Multimode
1300nm, 1550nm Single Mode
Fiber Optic Connectors ST or FC
Loss Budget*
(850nm, 1300nm,
Multimode (62.5/125m): 15dB
Single Mode (9/125m): 15dB
Interface (DCE) RS-422 , OR
 RS-485 (2 - 4 - wire)
Connector Terminal Blocks
Bit Error Rate 1 in 109 or better

* Contact factory for higher requirements
Visual Indicators
 LED, PWR, TD, RD, RS-485, Drive,
 Mode, Optic Sync
Standard 12VDC @ 200mA
Optional 115/230VAC
(with external power cube)
Operating -10 to 50C
Hi-Temp (optional) -20 to 70C
Storage -40 to 90C
Humidity 95% non-condensing
Physical (Wallmount Base)
Height (2.24 cm) 0.9"
Width (10.16 cm) 4.0"
Depth (7.87 cm) 3.1"
Weight (93.6 gm) 3.3 oz.


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