From: Matthias Schiffer > Sent: 29 March 2022 11:39 ... > I guess that would work. The fact that even the different > variants of the 8250 are implemented inconsistently makes this > especially ugly... It certainly puts a damper on the efforts to make > the handling of RS485 in serial drivers more generic. One thing to remember is that RS232 (IIRC really V.38) line driver chips are typically inverting. So the modem signals on a TTL level output will have the opposite polarity to that required on the actual connector. Normally a UART will have an 'active high' register bit for a modem signal that drives and 'active low' pin so you get the correct polarity with an inverting line driver. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
