The DIN-191 converts RS232 communications standard to the correct electrical signals required by RS485 devices. The DIN-192 extends the RS485 bus when more than 32 drivers are connected to a host computer. Both devices provide automatic control of bus direction without any handshaking signals from the host. The RS485 bus control is completely transparent to the user, allowing use of the host software for RS232 without modification. The RS485 is limited to 32 drivers to the communications port, and the DIN-192 amplifies the signal to drive up to 32 more drivers. It can also be used to boost signal levels when very long bus lines are used. Both units are optically isolated to 500 Vrms to protect the host computer from destructive voltages due to static or short circuits. Surge voltage protection is also provided on the RS485 output connections.

Unit pricing is $120.