Hi Jerson, I'm no expert but have dabbled a little, hope the following will be of some= help... In the link you gave, the purpose of "Home Automation Software" that runs o= n the=20 PC will be to create a redirection so that sending/receiving data to/from a= particular=20 IP address:port number will access your physical COM port. The IP address w= ill be=20 that of your PC. Another example of software that (I believe) can do this i= s Virtual=20 Serial Ports Emulator http://www.eterlogic.com/Products.VSPE.html (I've had= =20 experience using it, but not in the way you require). For example, let's say the local IP address of you PC 192.168.1.2, and your= PIC=20 serial device is connected to the PC's RS232 serial port COM2. You run redirection software on the PC, let's say it is configured to redir= ect IP port=20 8888 to COM2. >From this PC you can now Telnet into your serial device using the address= =20 192.168.1.2:8888 (or maybe just the port number 8888, I can't remember). Yo= u can=20 send and receive data in the Telnet window just like you would do on a sim= ple=20 terminal emulator such as Hypertrminal etc. What's more, you can now Telnet= into=20 your serial device from any other PC on your LAN using the address=20 192.168.1.2:8888. Why use port 8888? Well that's what they use in the example in the link you= gave.=20 There are 65536 ports, many of which have established uses, eg: 80 =3D HTTP= , 21 =3D=20 FTP. Basically you can use whatever you like as long as it doesn't conflict= with any=20 other port in use on your LAN.=20 http://en.wikipedia.org/wiki/TCP_and_UDP_port_numbers OK, so your serial port device can now be accessed over your LAN. Now, how = to=20 make your device accessable over the Internet? You need to make some change= s=20 in your modem/router. When connected to the Internet your router will have = a WAN=20 IP address (for example 203.197.202.67). What needs to be setup is a rule t= hat will=20 redirect external (Internet side) accesses to a certain port number (let's = use 8888=20 again) to a particular PC on the LAN side of the router and a particular po= rt number,=20 eg: 8888 =3D=3D> 192.168.1.2:8888 This kind of rule is variously described in different types of modem/router= s as Port=20 Forwarding, Virtual Server, etc. In other words you are creating a "hole in= your=20 firewall" that will directs Internet traffic to the local redirection runni= ng on your PC,=20 which in turn directs traffic to your serial device. So, if a user on the Internet want's to acces your serial device they need = to know=20 your WAN IP adress number and which port to use, then they wil be able to T= elnet=20 into it . eg. 203.197.202.67:8888. The tricky part then is that your WAN IP address most likely changes each t= ime=20 your modem/router connects. Some ISP's will offer a fixed IP address option= , so=20 that's one solution. Another option is to use a Dynamic DNS service which w= ill give=20 you a host name (so you don't have to use IP address number) . Here a coupl= e of=20 popular/good ones that offer a free service... https://www.dyndns.com/services/dns/dyndns/ http://www.no-ip.com/services/managed_dns/free_dynamic_dns.html Each has good tech info on how to set it up. Either your modem/router has s= upport=20 for particular DDNS providers in which case you configure it with hostname/= user=20 name/password, or you run a DDNS client application on one of the PC's on y= our=20 LAN. Then you will be able to Telnet into your serial device from anywhere on th= e=20 Interweb by using a URL, eg: my-serial-device.no-ip.org:8888 Have fun~! > Hello >=20 > I am a list lurker and this is my first post here. Please forgive > me & correct me if I am doing something wrong.=20 >=20 > What I am seeking to know is if how to connect my serial > communicating device (microcontroller based) to the internet via a PC > in between. I am seeking a Windows specific solution if there is > one. I do not mind writing my own application on the PC to do the > intermediate stuff, but, I do not know what that stuff should be.=20 >=20 > I found this link > http://www.kmitl.ac.th/%7Ekswichit/Ajay4/index.html which explains > precisely what I am trying to do. However, the PC part is not clear > to me. How can some device connected on a serial port of my pc go > onto the internet? Via telnet? ssh? ppp? slip?=20 >=20 > If you know any links that I can read up, I am eager to learn. Even > if there is something here on the list, please be so kind as to point > it out as I am new with the usage of this list.=20 >=20 > Thanks very much. >=20 > Cheers > Jerson Fernandes --=20 Brent Brown, Electronic Design Solutions 16 English Street, St Andrews, Hamilton 3200, New Zealand Ph: +64 7 849 0069 Fax: +64 7 849 0071 Cell: +64 27 433 4069 eMail: brent.brown@clear.net.nz --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .