The ModemSpeaker property determines if the modem speaker
is enabled when dialing the server. If the property is set to
False, the modem will be silent when dialing the telephone number and
establishing the connection. Note that setting this property to True
will not force the speaker on if the modem hardware has been
configured to explicitly disable the speaker.
To disable the speaker, the modem must support changes to the
speaker volume. Disabling the speaker is typically done by
instructing the modem to set the speaker volume to zero.