VoIP
ATA
with
router
function
User
Manual
25
VOIP
Setting
(IPG
‐
200/IPG
‐
110)
SIP
is
a
request
‐
response
protocol,
dealing
with
requests
from
clients
and
responses
from
servers.
Participants
are
identified
by
SIP
URLs.
Requests
can
be
sent
through
any
transport
protocol.
SIP
determines
the
end
system
to
be
used
for
the
session,
the
communication
media
and
media
parameters,
and
the
called
party's
desire
to
engage
in
the
communication.
Once
these
are
assured,
SIP
establishes
call
parameters
at
either
end
of
the
communication,
and
handles
call
transfer
and
termination.
SIP
Setting
Phone
Phone
book
PSTN
Line
(IPG
‐
110
only)
IPG
‐
200