At 12:52 27/08/99 -0400, you wrote:
>"Paul B. Webster VK2BZC" wrote:
>>   According to my discussions with the previous poster (I forget
>> whether on-list or off now), even acoustic couplers are required to be
>> type-approved.
>
>Yes, there are few standards, you can not inject "audio" levels higher
>than zero db (or dbm?) at phone lines, according to something I read
>many years ago... it could be complete different now... :)
>
>


The level is -10dBm ,but, ask your local telco what level the howler tone
is sent at!
But on the other hand you (Being the user) have to ensure that the level at
the MDF (Entry point to the exchange) is no more than -11dBm (Most cables
are matched to provide a 3dBr drop. So in a modem situation the levels are
like this

                                        *** MODEM ***
Originate       Cable           Exchange (Digital)      Cable           Terminat
e

-11dBm          -3dB                    -6dB            -3dB            0dB
-11             -14                     -20             -23             -23

                                Exchange (Analogue//digital hybrid)
                                        -6 to -12dB

                                        *** VOICE***

+3dBr           -3dB                    -6dB            -3dB            0dB
X level                                                         X level -12dB
(Human voice average = -15dBm)



Dennis