Panasonic KX-TDE100 Network Manual page 19

2.1.2 Network Configuration
Is there only a single IP network between 2 ends of a call?
A huge degradation in speech quality will be produced when calls are made through multiple IP networks as
shown below; therefore, it is recommended that you avoid establishing a VoIP network in this fashion.
PSTN/
BRI QSIG, etc.
IP Network 1 IP Network 2
IP Network 1 IP Network 2
IP Networking Guide 19