At 18:43 02/08/99 -0500, dave vanhorn wrote:
>>in germany they optionally send a billing impulse -- 15kHz, some 10 ms
>>duration -- which signifies a certain billing increment. works for all
>>billed calls, and is kinda helpful in some situations. but it can mess with
>>your modem communication quite a bit if your modem is not prepared and has
>>the appropriate filters :)
>
>You ain't just whistlin 15khz either. That is one HOT tone!

it has to be pretty hot, because the system wasn't designed for that
bandwidth, so the losses are not precisely calculable and there has to be a
pretty big margin. pretty lucky though that it doesn't actually get to the
ears :))

>As usual, the americans do it first, the europeans think (argue?) about it
>for a while, and come up with a better system.. Witness NTSC.

did you have billing tones here once? but better or not -- it might be
complicated to fit into the billing system here. germany's billing system
is based on those billing units, whereas here carriers are allowed to bill
however they like. and as far as europe goes: i think it's a pretty much
german only thing; i'm not aware of billing impulses in any other european
country. maybe because we're accountants by nature after all? :)

ge