the comm software that Maxstream provides does this somehow...when I pull t= he serial cable it comes up with an error...cannot communicate with device.= ..or something like that Genome wrote: Is there some function in the win32 sdk = that can tell a standard comm driver = that I'm not connected to a modem... I'm using simple createfile functions to open and close the port and = read/writefile functions to send/receive data to the pic... I found the = EscapeCommFunction that can directly acces the dtr and rts pins but dont = know how it will effect the port drivers operation as it automatically set = and unset this pins when you try to send and receive data... thanks... "Orin Eman" wrote in message = news:25b306ec0610201514m4e4731c8n3ad2da7365b667da@mail.gmail.com... > On 10/19/06, Genome wrote: >> Hello.. >> when Does the DTR pin(data terminal ready) of the RS-232 on the PC turns >> on.. and if it turns on is it like a single pulse and then turns off = >> again >> or is it always on while the USART has connection... I am planning to us= e = >> it >> to detect if the PC DB9 plug is connected to the PIC and if so try to >> initiate a handshake.. I dont know exactly but I've read somewhere that = >> the >> DTR pin is controlled by specific drivers of the communication PORT >> installed on windows... My question is only for the standard CommPort >> Driver... hope someone point me where I can read more about this stuff.. >> theres not much information on microsoft MSDN website except for win32 >> programming of the serial port but other than that not much details... >> >> thanks.. > > It depends on the PC software. Usually, it will be turned on when the > port is opened and left on until the port is closed. But if the > software thinks it's talking to a modem, it may not turn it on until > it's ready to dial or wait for a call and may turn it off in order to > hangup the modem. > > Orin. > -- = > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist = --------------------------------- Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ coun= tries) for 2=A2/min or less. -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist