The ModemSpeaker property determines if the modem speaker
is enabled when dialing the remote 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.