User Manual Analog Telephone Adaptor HandyTone-496
HandyTone-496 User Manual  Grandstream Networks, Inc. 
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i.e. the phone service we use for every ordinary phone call, or called POT (Plain Old 
Telephone), or circuit switched network. 
RTCP 
Real-time Transport Control Protocol, defined in 
RFC 3550, a sister protocol of the Real-time 
Transport Protocol (RTP), It partners RTP in the delivery and packaging of multimedia data, 
but does not transport any data itself. It is used periodically to transmit control packets to 
participants in a streaming multimedia session. The primary function of RTCP is to provide 
feedback on the quality of service being provided by RTP. 
RTP 
Real-time Transport Protocol defines a standardized packet format for delivering audio and 
video over the Internet. It was developed by the Audio-Video Transport Working Group of the 
IETF and first published in 1996 as RFC 1889
SDP 
Session Description Protocol, is a format for describing streaming media initialization 
parameters. It has been published by the IETF as RFC 2327. 
SIP 
Session Initiation Protocol, An IP telephony signaling protocol developed by the IETF 
(RFC3261). SIP is a text-based protocol suitable for integrated voice-data applications. SIP is 
designed for voice transmission and uses fewer resources and is considerably less complex than 
H.323. 
All Grandstream products are SIP based 
STUN 
Simple Traversal of UDP over NATs, is a network protocol allowing clients behind NAT (or 
multiple NATs) to find out its public address, the type of NAT it is behind and the internet side 
port associated by the NAT with a particular local port. This information is used to set up UDP 
communication between two hosts that are both behind NAT routers. The protocol is defined in 
RFC 3489. STUN will usually work good with non-symmetric NAT routers. 
TCP 
Transmission Control Protocol, is one of the core protocols of the Internet protocol suite. Using 
TCP, applications on networked hosts can create connections to one another, over which they 
can exchange data or packets. The protocol guarantees reliable and in-order delivery of sender 
to receiver data. 
TFTP 
Trivial File Transfer Protocol, is a very simple 
file transfer protocol, with the functionality of a 
very basic form of FTP; It uses UDP (port 69) as its transport protocol. 
UDP 
User Datagram Protocol (UDP) is one of the core protocols of the 
Internet protocol suite. Using 
UDP, programs on networked computers can send short messages known as 
datagrams to one 










