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left blank, or marked with a “*”, the information is taken from 
the Registrar eld. 
Authentication name  The name used for the Realm authentication. This may be the 
same as the user name, but must be lled in. 
Registration Interval  This is a request to the SIP server for when the registration 
should expire. OmniTouch 4135 IP automatically renews the 
registration within the time interval if the phone is still on and 
connected to the server. The default value is 1800 seconds. 
Proxy 1  Shall contain the proxy server used for Internet communication, 
if any. Can be left blank.
Proxy 2 
Outbound proxy 
Survivability enabled 
Survivability server
On phone: MENU > SETTINGS > ADVANCED > (PIN) > ACCOUNTS (6,2,1).
Nat traversal
NAT (Network Address Translation) is a rewall or router function that operates by 
rewriting the IP addresses in the IP headers as packets pass from one interface to the 
other. When a packet, for example, is sent from the inside, the source IP address and 
port are rewritten from the private IP address space into the address space on the 
outside (Internet).
NAT rewrites the addresses but leaves the packages themselves untouched. This kind of 
translation works ne for many protocols, but causes a lot of trouble for SIP packages 
that contain address information in their content (for example an INVITE request from 
one IP address to another). 
NAT traversal solves this problem, providing a “view from the outside” that makes it 
possible to replace the IP address in the SIP requests with the address shown on the 
other side of the rewall. 
Note that in some cases NAT traversal is not necessary. Some public service providers 
of IP telephony keep track of the actual IP address used to register a phone, and the 
one used in the SIP requests from the same phone, and then replaces the addresses in 
the SIP messages. 
STUN  STUN (Simple Traversal of UDP through NATs) is a protocol that 
assists devices behind a NAT rewall or router with their packet 
routing. STUN is commonly used in real-time voice, video, mes-
saging, and other interactive IP communication applications.. 
    The protocol allows applications operating through a NAT to 
SETTINGS