ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Telephone Talk

I once read about some US cordless phones operating at the Frequency of German Radio Bayern (FM 88.7 MHZ or something like that)... and anyone tuning in Bayern could listen to your conversations if you took such a phone to Germany...

Dave,
The routine on the new switches here for a phone off-hook but nothing dialed is weird:

Dial tone for about 20 sec.
SIT (three ascending tones)
Announcement repeated: "Please hang up and try again" for about 20 sec.
Quiet line for approx. 3 mins.
Howler for approx. 3 mins. (it fades in at the start over a period of about 10 secs.)

What then? Permanent signal or quiet line? Nope -- You get dumped back to dial tone!

After this one times out again, you go to SIT and 20 secs. of the announcement once more, then a dump to permanent quiet line until you hang up.

Quiet line here still has battery, and from the background noise it sounds as though at this point you're on very unbalanced power.

I'd left BT before these switches came into use, so I have no idea why it's arranged this way. Very strange.

Depending upon type and configuration, older switches would either let you listen to dial tone all day, or time out after 30 to 60 secs. In most cases after timeout you would get either N.U. tone or equipment engaged tone, followed by a quiet line.

Howler application wasn't automatic as it is now. It would be applied to the line manually if a number was reported as always busy and verification showed the line just off-hook.

Mike,

Cordless phones designed for the "wrong" market have been a problem here as well. I'm not sure if 73.35 MHZ is authorized for cordless phones in NZ, but strong harmonics certainly shouldn't be radiated. According to my data, the 3rd harmonic of 73.35 falls right in NZ TV channel 10, for a start.

Here's a summary of the cordless p;hone frequencies authorized in the U.K:
http://www.radio.gov.uk/publication/ra_info/ra193.htm



[This message has been edited by pauluk (edited 10-19-2003).]

Paul:
Is the howler tone there anything like the obnoxious one here in the US?

Time-out after 30 seconds of not dialling or more than 10 seconds between digits, line goes to busy forever (you know that, somebody knocks over the handset in the late evening and the next morning you find it there, and it's on the busy tone). Priority Telecom is different though, there the line goes dead after some time, don't know how long. They didn't document their service nearly as good as Telekom Austria did (they published all that info on the first pages of the old directories, before those pages were filled with ads for adult hotlines).

Here's the US "Receiver Off Hook" tone:
http://www.telephonetribute.com/audio/off_hook_alert.wav

According to the website listed above:

No, it's rather different, but certainly obnoxious!

Here's a sample I recorded from my line.


[This message has been edited by pauluk (edited 10-20-2003).]

Paul, that almost sounds like something out of a sci-fi movie before everything blows up!

Paul:

After the end of the busy tones here you get :

either clunk, click and just dead silence if you've any line powered feature phones connected their displays will go blank. Or else a kinda weird fading of the busy tone and the a click to complete silence and the power is removed (again feature phones and memory phones loose power)

It has one very handy effect. If I leave my Siemens DECT phone off hook accidently once the power to the line is cut it automatically hangs up!

If the power is completely cut however i have no idea how it detects when the phone is back on hook though. I presume it must keep some kind of very low power DC on the line regardless.

Don't know when that was, but since the early days, cordless phones used the 46/49 Mhz band, although the TX frequency was created by a 16 Mhz or so crystal oscillator, and multiplied.