Digital phone network 2

[macker66]

What is required for me to connect my laptop (which has a standard 56k modem) onto the internet through a digital telephone network?
T'I'A'
Ste

 

[Crustyoldbloke]

A cable with the correct plugs on each end, i.e. a standard modem to phone jack cable, unless you've got something unusual. I'm in the UK and that is what you need here, could be different in another country I suppose. Treat your children well. They get to choose your nursing home!
Phil
Please tell me if the answer I gave was helpful or a bus ride out. Without your feedback I won't know.

 

[macker66]

Thanks Phil, I have the correct cables (rj45 to rj11) but I read that an analogue modem could get burnt out, because digital runs on a higher voltage?
I wonder if an ISDN modem would do?

 

[Crustyoldbloke]

Seeing your comment, I thought I might just have a quick look on GOOGLE. Couldn't see anything untoward with the exception of Germany. Treat your children well. They get to choose your nursing home!
Phil
Please tell me if the answer I gave was helpful or a bus ride out. Without your feedback I won't know.

 

[pansophic]

Isn't the answer always, "It depends?"

Your analog modem can only attach directly to the digital telephone network through an analog telephone line. For certain telephone systems, analog adapters are made that allow you to plug your modem into the adapter, which plugs into the ISDN or proprietary digital telephone line.

The fact that you are using a cable that is RJ-45 to RJ-11 indicates that what you are attempting to do probably will not work. Analog telephone lines are RARELY put on RJ-45 outlets. However digital telephone lines are frequently put on both.

A simple way to determine if your modem will work on the phone line is to turn the telephone over. If it has a REN or Ringer Equivalency Number, then your modem should work. If it does not, then the modem should not work (US of course).

I've heard the urban legend about digital lines destroying analog modems, but have never seen that happen. There is no voltage difference in any of the telephone systems registered with the FCC for use in the US. That is because it is a National Electric Code requirement that the telephone instruments use "low-voltage" which translates to less than 50 volts. That is why the battery plant in a telephone system is -48 volt, just within tolerance. Of course there is compensation for voltage drop, and most battery plants actually operate at -54 VDC.

There may be a current difference for digital instruments, but I haven't seen that either. Most operate at 40mA or less, just like their analog counterparts.

And considering that Ring voltage is frequently in excess of 200 VAC (20-30 Hz) and the modems handle this without an issue, it seems highly suspect that the modems would have a problem.

All of that said, there is a company called Konexx who make an acoustic adapter (fits over the handset) with which I have achieved rates of up to 14.4K. They also make a handset cord adapter that I have used to achieve rates up to 28.8K. You will never achieve rates over 33.6K with these types of devices, but they are functional with every make and model of digital instrument I have ever tried them with. A definite must for the road warrior.

I found the handset cord adapter at:

http://www.niceelectronics.com/computer/indexMy.htm?discr11975.htm

Good luck!
pansophic

 

[macker66]

Thanks all, this all arose when a colleague tried to connect through a digital network that failed. I will look into getting the $108 box for him.
(i'm in th UK if that makes a difference?)

 

[pansophic]

I've used the Konexx device in Germany, but have never been to the UK. It should work anywhere, but you never know. I saw another device called a LineStein, which appears to be similar to the Konexx except that it adjusts IO levels automatically.

http://www.hellodirect.com/catalog/product.jhtml?PRODID=10173&CATID=15303

pansophic

 

[macker66]

Perfect! You are both on my helpful list now, thanks again.