Olimex's USB-4SERIAL Lets You Really Scale Your RS232, RS485, and TTL Serial Connectivity
With four RS232 and TTL ports, one switchable to RS485, you can add as many of these boards to your PC as you have free USB ports.
Bulgarian open hardware specialist Olimex has announced a new board design for those who need a fistful of flexible serial ports on hardware with only a USB port for connectivity: The USB-4SERIAL.
"USB-4SERIAL is an industrial grade -45 [to] +85°C [-49 to 185°F] Open Source Hardware USB-C type connector USB 2.0 High Speed to four RS232-level or TTL-level serial ports," explains Olimex founder Tsvetan Usunov of his latest board design, which is being released both as a ready-to-use fully-assembled gadget and open-hardware design files.
Accepting a USB Type-C cable at one end, the USB-4SERIAL delivers exactly what it promises: four nine-pin RS232 serial ports. For those looking for transistor-transistor-logic (TTL) level connectivity, the four ports are also brought out to three-pin headers — making them compatible with UART connections on single-board computers and the like. There's even support for switching the fourth RS232 port into an RS485 port, should you need it.
As many USB-4SERIAL boards can be connected to a host as it has free USB ports, Usunov promises, offering the ability to scale a single system to a truly impressive number of serial devices. The only real catches: while the serial chipset offers up to 12Mbps data throughput using the DB9 connectors for RS232-level communication limits this to 400Kbps, and only the first serial port has hardware flow control.
The USB-4SERIAL is now available to order on the Olimex website at €18 (around $19) before volume discounts, with design files and driver source available on GitHub under the reciprocal GNU General Public License 3.