Various application-centric user interface techniques are described. An optical transmitting and receiving module holder includes a first optical module holder section and a second optical module holder section. In certain instances, numbers that are designated as private may show up on a called party’s caller identification terminal since the caller identification block for the private number was not properly requested at the time of requesting a private number. The second pinched-in area includes third and fourth wall portions that extend inwardly toward an interior of the main body, and a second end wall portion connecting the third and fourth wall portions. Preferably, the gate insert is retained by a gate insert plate that is disposed between the cavity plate and the nozzle assembly.