This port-powered, two channel converter allows your computer to communicate longer distances by converting TD and RD RS-232 lines to RS-485 signals. RS-485 also provides multi-drop capability.

Model 485SD9RJ features Automatic Send Data Control which enables the driver when data is present on the RS-232 side. Control of the driver is automatic at speeds up to 115.2 kbps.

The converter is powered from the RS-232 data and handshake lines whether the lines are high or low. No handshake line change is necessary to control the data lines. The RS-485 driver is enabled with each bit of data. The RS-485 receiver is disabled when the driver is enabled and is enabled when the driver is disabled.

This converter is suitable for field service, where a power supply would add clutter, or anywhere you need compact, easy-to-use, economically priced serial conversion.

Port-powered, 2-channel converter changes RS232 TD and RD to RS485 for longer distance and multidrop function. Automatic Send Data Control enables driver when data is present on RS232 side. Powered from RS232 data and handshake lines (high or low).

Port-powered, 2-channel converter changes RS232 TD and RD to RS485 for longer distance and multidrop function. Automatic Send Data Control enables driver when data is present on RS232 side. Powered from RS232 data and handshake lines (high or low). External power optional - PS sold separately.

Model 485CON, RS-232 to RS-485 converter, converts unbalanced, full-duplex RS-232 signals to balanced, full-duplex or half-duplex RS-485 signals. RS-485 is an enhanced version of the RS-422 balanced line standard. It allows multiple drivers and receivers on a two-wire system.

The RS-232 port uses a male DB-25P type of connector with pins 2 (TD input) and 3 (RD output) supported. Protective Ground (pin 1) and Signal Ground (pin 7) are also connected. The RS-485 port uses a female DB-25S type of connector with Send Data outputs on pins 2 and 14, and Receive Data inputs on pins 5 and 17. Protective Ground (pin 1) and Signal Ground (pin 7) are connected through to the RS-232 connector.

The polarity of the two RS-485 lines must be correct. With no data being sent, the RS-232 line should be negative and the RS-485 "A" terminal should be negative with respect to the "B" terminal. If your equipment uses a " " and "-" naming scheme, in most cases the "A" line will be connected to the "-" and the "B" line will be connected to the " ". The RS-485 driver must be enabled when checking the polarity of the output of a RS-485 driver. On this connector, the RTS input (pin 4), on the RS-232 side must be raised to enable the RS-485 driver.

Figure 1 shows how to interconnect two RS-485 converters using two signal wires. The resistors Rt are optional, depending on the line length, baud rate, etc. The resistors should be about the impedance of the line used, which is normally about 120 Ohms each. Termination resistors are installed only at each end of the RS-485 multi-drop network. RTS must be off (low or marking) to receive and on (high or spacing) to transmit. Both RTS’s should not be on at the same time. Although you will not damage anything, the data sent will be garbled. If both RTS lines are off, the line may be floating and random data may appear on the outputs. Your protocol should allow for this if it can happen.

Up to 32 receivers can be driven by any one generator. This allows you to put together large systems with many drop points. The termination resistors should be located at approximately opposite ends of the system.
An external power supply is required (not included, sold separately).

Model 485COSR, RS-232 to RS-485 converter, converts unbalanced, full-duplex RS-232 signals to balanced full-duplex (4-wire) or half-duplex (2-wire) RS-485 signals.

The RS-232 port has a female DB25S connector with pins 2 (TD input) and 3 (RD output) supported. Protective Ground (pin 1) and Signal Ground (pin 7) are also passed through. Pins 4 (RTS) and 5 (CTS) are tied together. Pins 6 (DSR), 8 (CD), and 20 (DTR) are tied together, but not passed through the converter.

The RS-485 port has a male DB25P connector with Send Data outputs on pins 2 and 14, and Receive Data inputs on pins 3 and 16, or 5 and 17. No special software requirements are needed since the RS-485 driver is enabled by the first transition on the RS-232 side of the Transmit Data line (Pin 2). Any transmission on the TD line keeps the RS-485 driver enabled by preventing the mono-stable multi-vibrator from timing out. The transmitter is disabled approximately 1 ms after the last transmitted character. This 1 ms timeout allows continuous transmission of data at 9600 baud or higher.
A 12 VDC external power supply is required (not included, sold separately).

Model BB-485TBLED converts unbalanced, full-duplex RS-232 signals to balanced, full or half-duplex RS-422 or RS-485 signals. RS-485 is an enhanced version of the RS-422 Standard allowing multiple drivers and receivers on a two-wire or four-wire system.

The RS-232 port, configured as a DCE port, has a female DB25 connector with pins 2 (TD input), 3 (RD output), and 7 (Signal Ground) supported. Pins 4 (RTS) and 5 (CTS) are tied together, and pins 6 (DSR), 8 (CD), and 20 (DTR) are also tied together. Pins 1 (Frame Ground) and 7 (Signal Ground) are connected straight through to the RS-485 terminal blocks. The RS-485 terminal blocks support Transmit Data (A-) and (B ), Receive Data (A-) and (B ), Frame Ground, Signal Ground, and 12 VDC input.
Model BB-485TBLED required a 12 VDC external power source (power supply not included, sold separately).

Model BB-485PTBR converts unbalanced RS-232 signals to balanced, full or half-duplex RS-485 signals. RS-485 is an enhanced version of the RS-422 Standard allowing multiple drivers and receivers on a two-wire system. The RS-232 port has a female DB9 connector with pins 2(RD), 3(TD), and 5(SG) supported. Pins 7(RTS) and 8(CTS) are tied together. Also pins 6(DSR), 1(CD), and 4(DTR) are tied together, but not passed through the converter. The RS-485 port has an 8-position pluggable terminal block connector. Model BB-485PTBR supports baud rates from 300 to 115.2K.
12VDC power supply required (not included, sold separately).