Model TC1540
RS-232, RS-422, RS-485 Fiber Optic Modem


  • Async Data Rates Up to 500 Kbps* 
  • Distances up to 80km
  • Multimode or Single Mode (850/1300/1550nm)
  • Switch-Selectable 2-wire or
     4-wire RS-485
  • Mix & Match RS-232/422/485
  • Built-In Test Signal Generator
  • 8 LEDs & 8 DIP Switches for Diagnostics
  • Low Power Consumption
  • Local Dry Contact Alarm
  • High Temperature (-20C to 70C) Version Optional


The TC1540 is a highly versatile 2-wire RS-485 fiber optic modem that can mix or match RS-232, RS-422 or RS-485 (2-wire or 4-wire) interfaces, as required.  For example, a user could have a 2-wire RS-485 interface on one end and an RS-232, RS-422 or 4-wire RS-485 interface on the other.  2-wire RS-485 versions can be converted to 4-wire RS-485 by simply changing a DIP switch.

The TC1540 supports asynchronous data rates up to 500 Kbps*, depending on the electrical interface, and is compatible with all popular types and sizes of multimode (850/1300nm) or single mode (1300/1550nm) fiber optic cable.  Distances up to 80km are possible.

Diagnostics include a built-in Test Signal Generator that verifies both device and fiber optic link operation. This feature benefits users by helping technicians verify that both local and remote devices and the fiber optic link are operating normally. Local and Remote Loopback Tests are available to verify electrical and fiber connections.

Eight DIP switches and seven LED indicators are provided to help installation and troubleshooting.  An extreme temperature version (-20C to 70C), Model TC1540T, is also available.

Fiber optic connectors are ST or FC.  Electrical connectors are terminal blocks.  Power is 12VDC at 250mA; optional 24VDC or 115/230VAC with an external power cube.

TC1540 Specifications

Data Rates
Async RS-232, RS-422, RS-485 up to 500 Kbps
Transmitter LED/ELED
Receiver PIN
Wavelength 850nm/1300nm multimode
  1310/1550nm single mode
Fiber Optic connectors ST (FC optional)
Loss Budget 15dB multimode 850nm/1310nm @62.5um
  20dB single mode 1310nm @9um
Electrical - Select One
(DCE) RS-232 Removable Terminal Block
(DCE) RS-422/530 Removable Terminal Block
(DCE) RS-485 Removable Terminal Block
Bit error rate
RS-232, RS-422, RS-485 1 in l09 or better
Visual Indicators
System "POWER A," "POWER B," "ALARM,"
RS-232, RS-422, RS-485 "RxD," "TxD,"
Standard I2VDC @250mA
optional: 115 or 230VAC with external power cube
optional: -24 or -48VDC  
Operating -100C to 500C
Hi-Temp (optional) -20C to 70C
Storage -400C to 900C
Humidity 95% non-condensing
Micro Size Stand Alone Height (2.79 cm) 1.1"
  Width (12.70 cm) 5.0"
  Depth (6.35 cm) 2.5"
  Weight (180 gm) 5.1 oz.

Typical Application (Application Questions)

The TC1540 typically interconnects CPUs or Host Controllers with remote terminal units (RTUs).  It is frequently used in SCADA, Traffic Control, Manufacturing Process Control and Security applications