I wondered about the who modem works...
the modems we saw contains two RJ11 inputs where called Line and Phone
who knows the specific function of of each one???
thankx so much ...

 

Hi,
The 'line' is where you connect the phone jack wire. The 'phone' is if you want to attach a telephone to the same line, but you don't have a suitable outlet (eg if you have only one socket, and have to connect both the modem and phone to it)

Moving on to internal function, I don't know the exact stuff, but this is (I think) right:

I) It, first of all, consists of a 'phone' circuit: ie. something that can separate the stuff you listen from the stuff you speak. Phone lines are generally in a duplex mode, ie the same 2 wires are used for sending and recieving the sound). Also, it has capability for DTMF tones, which are used for dialling (the beeps you hear when you dial a phone)

II) The data to be transmitted is first sent to a 'modulator', which converts it into suitable signals to send and sends it.

III) The data recieved is fed to a 'demodulator', which performs the opposite function of a modulator: it converts the recieved signal into the original data.

Newer modems are much more complex than this, with features like line testing and adjustment, variable speeds, voice and data functionality, and lots more. Anyway...hope that helps...if you need more info on modems in general, check this out:
How Modems Work

 

thanks curiouscritic..

its really usefull information and i think it make more clear to under stand the functionallity of modem.

but i have onther question about the structure of modem....
especially the internal modem ..

we know that the most external modems uses RS232 as interface with PC
ok .. the internal modem what we call the interface and how we can reach to it through PC .... suppose i want to make programm to send data to internal mode...

is it possible .....


with greate thanks

Ahmed.

 

Hmm...I don't exactly understand what you're asking, but the internal modems interface to the computer through the PCI ports, they are sort-of like slots, where you can fix different types of cards. Modems are one of them. You can also add soundcards, videocards, TV Tuners, Ethernet, etc. I don't know what you mean exactly by 'sending data to internal mode' though. Hope that helps...

 

Originally posted by Ahmed@Aug 28 2005, 09:54 AM
we know that the most external modems uses RS232 as interface with PC
ok .. the internal modem what we call the interface and how we can reach to it through PC .... suppose i want to make programm to send data to internal mode...
.

[post=9976]Quoted post[/post]​

Hi Ahmed,
If I understand your question correct, you want to know how you connect to an internal modem in your PC?

This is normally done the same way as you connect to a serial (RS232) connected modem. You use the COMx serial port the modem is connected to in the setup. When you install the modem, you assign it to a COM-port (ex COM1 - 4)

When you then write to the selected COM-port you are communicating with the modem, or through the modem if you have made a call.

I hope this made some sense

TOK

 

Thanks for cooperating with me ........