Nortel 1110 User Guide

 Nortel IP Softphone 2050

IP Phones

Description, Installation, and Operation

After the customer enters this information, the IP Softphone 2050 contacts the 
Node Master, which selects a TPS with sufficient capacity to register the 
IP Softphone 2050. The IP Softphone 2050 contacts the chosen TPS and, if 
the IP Softphone 2050 is valid, registers it with the system. The registration 
information is then saved to the IP Softphone 2050.

The USB Headset Adapter provides the IP Softphone 2050 with a fixed loss 
plan compliant with the TIA-810A specification. If other headsets or audio 
devices are used, the loss plan is unknown and undefined. Nortel supports the 
resolution of audio problems only for the USB Headset Adapter.

Echo can be generated electrically when there is an impedance mismatch, or 
generated acoustically by feedback from a speaker or ear piece to a 
microphone. Any echo that is ultimately returned to the IP Phone is more 
noticeable to the listener because of the additional delay introduced by the IP 
connection.

The Voice Gateway Media Card has echo cancelers included as part of its 
function that cancels echo generated on the TDM side of the Media Gateway. 
When audio goes through the Voice Gateway Media Card, the echo 
cancellers are enabled.

The IP Softphone 2050 has no echo canceller, so a slight echo from acoustic 
coupling on the headset can occur in some call situations.

Buffer underruns and overruns can occur since there is no sample clock at the 
receiving end of an IP audio stream synchronized to the transmitting clock. 
The buffer overruns and underruns are corrected by two mechanisms, both of 
which apply to the IP Phones and the DSPs on the Voice Gateway Media 
Card.