The TCF-142 Series converter is equipped with a multiple interface circuit that can handle RS-232, or RS-422/485 serial interfaces and multi-mode or single-mode fiber. TCF-142 converters are used to extend serial transmission distance up to 5 km (TCF-142-M-ST multi-mode fiber) or up to 40 km (TCF-142-S -ST single-mode fiber). Note that the RS-232 and RS-422/485 interfaces cannot be used on the same TCF-142 at the same time to convert to fiber.

Why Convert Serial to Fiber?

Fiber communications not only extends the communication distance, but is also beneficial in many other ways, such as:

• Immunity from electrical interference
  Optical fiber is not affected by electromagnetic interference or radio frequency interference, provides a clean communication path, and is immune from cross-talk.
• Insulation
  Optical fiber is an insulator; the glass fiber eliminates the need for using an electric current as the data transmission medium.
• Security
  Optical fiber cannot be tapped by conventional electronic means, and is very difficult to tap into optically. Furthermore, radio and satellite communication signals can be easily captured for decoding.
• Reliability and Maintenance
  Optical fiber is immune from adverse temperature and moisture conditions, does not corrode or lose its signal, and is not affected by short circuits, power surges, or static electricity.

DIP Switch Selectable Terminator

For many products of this type, the termination resistor is set by a jumper located inside the product's casing, so that the user must open the casing to disable or change the resistor's strength. Moxa offers a better solution. TCF-142's terminator is set with a DIP Switch located on the outside of the converter's casing.

Auto Baudrate Detection

TCF-142 incorporates a method for automatically detecting the serial signal's baudrate by hardware. This is an extremely convenient feature for the user. Even if a device's baudrate changes, the signal will still be transmitted through the converter.

Ring Operation

To allow one serial device to communicate with multiple devices connected to a fiber ring, you should configure TCF-142 for "ring mode" by setting DIP switch "SW4" to the "On" position. The Tx port of a particular TCF-142 unit connects to the neighboring converter's Rx port to form the ring. Note that when one node transmits a signal, the signal travels around the ring until it returns back to the transmitting unit, which then blocks the signal. Users should ensure that the total fiber ring length is less than 100 km.

NOTE: Only TCF-142-M-ST v2.1 and TCF-142-S-ST v2.3 (and later versions) support ring mode.

Automatic Data Direction Control (ADDC™)

ADDC™ is a MOXA leading technology that uses a clever hardware solution to take care of the RS-485 data direction control problem. The TCF-142 Series converter uses embedded ADDC™ technology, a hardware data flow solution, to sense and control data direction automatically, making the hand shaking signal method unnecessary.