Warning: Prolific has deliberately broken support for counterfeit and older chips in recent drivers.
Linux has the best legacy support. Most Ucom 208-2 adapters work out of the box with the cdc_acm or ch341 kernel modules. ucom 208-2 driver
lsusb
Look for "Prolific Technology Inc." or "QinHeng Electronics CH340". Look for "Prolific Technology Inc
The driver inside the UCOM 208-2 consists of: Thus, the "driver" in the name refers to
Thus, the "driver" in the name refers to the active, half-duplex, auto-flipping differential line driver.
| Parameter | Value | |-----------|-------| | RS-232 side | DTE pinout (DB9 female), RxD, TxD, GND only (no hardware handshake needed) | | RS-485 side | 2-wire half-duplex (A/B), screw terminal or DB9 male | | Isolation | Non-isolated (common ground between sides) | | Baud rate | Up to 115.2 kbps (often 9600–38400 in practice) | | Termination | Built-in switchable 120Ω termination resistor | | Bias resistors | Some versions include failsafe biasing (750Ω pull-up/pull-down) | | Supply | External 5–24V DC or bus-powered from RS-232 control lines |