Loud 'n' proud  By Roulla Yiacoumi August 13, 2005 The Kyocera
KX 440.  The Kyocera KX 440.  Say the word "walkie-talkie" and
memories of being a kid running around with a little talking
plastic box come to mind. Today, this style of instant
communication is being installed on an increasing number of
mobile phone handsets under the name Push-to-talk (PTT).  By
pressing the PTT button, you can send an instant communication
to one person or a group simultaneously. There's no need to make
a phone call. Rather than using radio frequencies to transmit
your voice, PTT uses the existing GSM and CDMA mobile phone
networks.  Consider PTT as a spoken SMS; it's ideal for short
bursts of talking, but is no match for a phone call. To talk,
you hold down the PTT button on the phone, then release it when
finished. You can't speak or interject until the current speaker
takes their finger off the button.  There are two telcos
offering PTT services in Australia: Telstra and Optus. What's
interesting is that they've chosen to t