The following pictures show some SuperCom specific timings ("direction" switch latency) with the RS-485 controlled through the onboard COM1 and through serial ports on a multiport PCI card.
The data monitor used was capturing data on a Notebook and was not involved in data communications.
The captured data packet was 82 bytes long ("A012345....B").
The last event shows only the RTS signal dropping.
it took 0.36ms* = 360 µs (micro seconds)
Serial ports on a PCI card
it took 0.45ms* = 450 µs (micro seconds)
*Direction switch latency was on the above tests constantly less than 1 ms.
The switch latency in SuperCom is also related to the transmission speed (bps). We measured a latency of about 3.50ms when transmitting with 2400 bps, about 1.20ms with 9600bps and below 1 ms when higher than 9600bps. The type of serial port, the number of open serial ports and running on a busy server may have affect on the result.
The RS-485 support, in SuperCom, is easily activated by setting the ComType or by a function call.
Please also ask for the 'SuperCom Technical Library -- RS-485 and 9-Bit Multidrop Communications Paper'.
The DEMO software found online, even when activating RS-485, are working with limited functionality, especially when it comes to response timing. The complete functionality is contained only in the licensed version.