The TCC-80-DB9 provides complete signal conversion between RS-232 and RS-422/485, without requiring an external power source. It supports both half duplex 2-wire RS-485 and full duplex 4-wire RS-422/485, either of which can be converted between RS-232's TxD and RxD lines. In addition, the TCC-80-DB9's 15 KV ESD protection guards against damage from electrostatic discharge. Automatic data direction control is also provided for RS-485, in which the RS-485 driver is enabled automatically when the circuitry senses the TxD output from the RS-232 signal. This means that no programming effort is required to control the transmission direction of the RS-485 signal.

Port Power over RS-232
The RS-232 port of the TCC-80 is a DB9 female socket that can connect directly to the host PC, with power drawn from the TxD, RTS, or DTR line. Regardless of whether the signal is high or low, the TCC-80 can obtain enough power from the data/handshake line. However, external power can be used if the handshake line is not available, if the serial cable is too long, or if the RS-232 device is a low power device. For external power, a 5 to 12 VDC power supply can be connected using an adaptor or a USB power cord.

Optional External Power
Termination is a critical requirement for port-powered devices such as the TCC-80. In most circumstances, termination resistors are used if the RS-422/485 cable is longer than 100 m. Regardless of how much the data signal is dissipated, the termination resistors absorb more than 75 mW of power. In other words, if long distance RS-422/485 transmission or termination is required, then an external USB power cord or DC power supply should be used.

Port Power Dissipation
When installing a TCC-80 converter, it is important to pay attention to power consumption, RS-232 cable length, and RS-422/485 transmission distance. In general, the TCC-80 obtains 50 mW from the power source. Standard PC COM ports can provide 70 to 90 mW of power if the TxD, RTS, and DTR lines are connected. Moreover, the RS-232 cable should be shorter than 15 m (@ 9600 bps) to ensure that less power is lost from the host/device to the TCC-80. The remainder of the supplied power is used for transmitting the RS-422/485 signal.

Features

• External power source supported but not required
• Compact size
• Converts RS-422, and both 2-wire and 4-wire RS-485
• RS-485 automatic data direction control
• Automatic baudrate detection
• 15 KV serial ESD protection
• Built-in 120-ohm termination resistors