RS 232 & USB (Urgent)

[haroonrashid]

Hi Every one... I need any expert's help please... I am handling one device (circuit) which works as to switch on 240 VAC Electric device....and its using RS232 protocol and using only 3 pins of Serial Com Port (2 signals only) (1. Ring Indicator (RI) 2. Data Carrier Detect (DCD)) as input from External Serial Modem...... now my concern is....I want to use External USB Modem....but can't classify how??? Can anybody please help me....???? its quite urgent....Thanks in advance.

 

[Sceadwian]

Simply swap the two, there should be no difference.

 

[haroonrashid]

Simply swap the two, there should be no difference.

Thanks for your prompt reply....
But How Bro? I can't understand....
I am using only 2 signals from RS232 (DB9) which are Ring Indicator & Data Carrier Detect but in USB we have 4 cables out of 2 works for data....1 sent & other receive but how do I shift my cable & which one to where? Thanks but plz clear me a bit more

 

[canadaelk]

I believe you mean RS232 or serial port (not modem) and USB port (not modem). Google "usb to rs232" to get there. E

 

[haroonrashid]

I believe you mean RS232 or serial port (not modem) and USB port (not modem). Google "usb to rs232" to get there. E

I am using Serial External Modem which is working on RS232 protocol by using DB9 Pins Male & Female Connectors & I want to modify it with USB External Modem & Ofcourse USB Cable. Can you please help me? Thanks

 

[Nigel Goodwin]

You basically can't connect a USB modem to a simple serial port, and converters don't usually work that way round.

Simply plug the USB modem in the PC and rewrite the PC software accordingly - although generally all you would have to do is set the virtual serial port in the software to the USB modem.

Assuming this is a USB GSM modem?, I've currently got a Huawei E160 plugged in my PC, and it simply appears under COM20 as a virtual serial port.