Yealink SIP-T2 SERIES Administrator's Manual page 694

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
Details of Configuration Parameters:
account.X.sip_server.Y.transport_type
(X ranges from 1 to 16, Y ranges from 1 to 2)
Description:
Configures the type of transport protocol for account X.
0-UDP
1-TCP
2-TLS
3-DNS-NAPTR
If the value of the parameter is set to 3 (DNS-NAPTR) and no server port is given,
the IP phone performs the DNS NAPTR and SRV queries for the service type and
port.
X ranges from 1 to 16 (for SIP VP-T49G/SIP-T48G/T46G/T29G)
X ranges from 1 to 12 (for SIP-T42G)
X ranges from 1 to 6 (for SIP-T41P/T27P)
X ranges from 1 to 3 (for SIP-T40P/T23P/T23G)
X ranges from 1 to 2 (for SIP-T21(P) E2)
X is equal to 1 (for SIP-T19(P) E2/CP860)
Web User Interface:
Account->Register->SIP Server Y->Transport
Phone User Interface:
None
account.X.naptr_build
Description:
Configures the way of SRV query for the IP phone to be performed when no result is
returned from NAPTR query for account X.
0-SRV query using UDP only
1-SRV query using UDP, TCP and TLS
X ranges from 1 to 16 (for SIP VP-T49G/SIP-T48G/T46G/T29G)
X ranges from 1 to 12 (for SIP-T42G)
X ranges from 1 to 6 (for SIP-T41P/T27P)
672
Parameters
?m=mod_data&p=account-regis
ter&q=load&acc=0
Permitted Values
0, 1, 2 or 3
0 or 1
Default
0
0