Method and apparatus for controlling the transmit volume level of a speakerphone

1. A method for controlling the transmit volume level of a speakerphone comprising: receiving a transmit audio signal; and if the speakerphone is in a speakerphone mode: measuring a send output level of the transmit audio signal; comparing the send output level of the transmit audio signal with a send output level threshold value; and controlling the send output level of the transmit audio signal based upon the comparison of the send output level of the transmit audio signal and the send output level threshold value using automatic gain control and further comprising: determining a send loudness rating (SLR) target difference value between a speakerphone SLR target value and a handset SLR target value; determining the send output level threshold value based upon the SLR target difference value.

2. The method of claim 1 , wherein the controlling includes amplifying the send output level of the transmit audio signal using automatic gain control if the send output level of the transmit audio signal is less than the send output level threshold value.

3. The method of claim 2 , wherein amplifying the send output level of the transmit audio signal includes adding the difference between the send output level threshold value and the send output level of the transmit audio signal as a gain to the send output level of the transmit audio signal.

4. The method of claim 1 , wherein the controlling includes passing the transmit audio signal with substantially the same send output level if the send output level of the transmit audio signal is greater than or equal to the send output level threshold value.

5. The method of claim 1 , wherein the speakerphone is a digital speakerphone, and determining the send output level threshold value based upon the SLR target difference value further comprises:

determining a digital handset nominal send output value associated with a reference digital handset telephone;

determining a digital speakerphone nominal send output value associated with a reference digital speakerphone, the digital speakerphone nominal send output value being equal to the digital handset nominal send output value minus an SLR target difference between a digital speakerphone SLR target value and a digital handset SLR target value; and

determining the send output level threshold value by adding an digital speakerphone enhancement factor to the digital speakerphone nominal send output value.

6. The method of claim 5 , wherein the digital speakerphone enhancement factor is in a range of −2 dBV to −3 dBV.

7. The method of claim 5 , wherein the send output level threshold value is in a range of −22 dBV to −25 dBV.

8. The method of claim 1 , wherein the speakerphone is an analog speakerphone, and determining the send output level threshold value based upon the SLR target difference value further comprises:

determining a digital handset nominal send output value associated with a reference digital handset telephone;

determining an analog handset nominal send output value associated with a reference analog handset telephone, the analog handset nominal send output value being equal to the digital handset nominal send output value minus an SLR target difference between an analog handset SLR target value and a digital handset SLR target value;

determining an analog speakerphone nominal send output value associated with a reference analog speakerphone, the analog speakerphone nominal send output value equal to the analog handset nominal send output value minus an SLR target difference between an analog speakerphone SLR target value and a digital handset SLR target value; and

determining the send output level threshold value by adding an analog speakerphone enhancement factor to the analog speakerphone nominal send output value.

9. The method of claim 8 , wherein the analog speakerphone enhancement factor is in a range of −2 dBV to −3 dBV.

10. The method of claim 8 , wherein the send output level threshold value is in a range of −2 dBV to −26 dBV.

11. The method of claim 1 , wherein if the speakerphone is in a handset mode, the send output level of the transmit audio signal remains substantially the same.

12. A method of controlling the transmit volume level of a speakerphone comprising: receiving an audio signal from a user of a speakerphone; altering the audio signal by applying an automatic gain control function to the audio signal; and communicating the altered audio signal over a communications network; wherein altering the transmit audio signal includes: measuring an output level of the audio signal; comparing the output level of the audio signal with an output level threshold value; and altering the output level of the audio signal based upon the comparison of the output level of the audio signal and the output level threshold value and further comprising: determining a send loudness rating (SLR) target difference value between a speakerphone SLR target value and a handset SLR target value; determining the send output level threshold value based upon the SLR target difference value.

13. An apparatus for controlling the transmit volume level of a speakerphone comprising: an automatic gain control module, the automatic gain control module configured to: receive a transmit audio signal; and if the speakerphone is in a speakerphone mode: measure a send output level of the transmit audio signal; compare the send output level of the transmit audio signal with a send output level threshold value; and control the send output level of the transmit audio signal based upon the comparison of the send output level of the transmit audio signal and the send output level threshold value using automatic gain control and wherein the send output level threshold value is determined based upon a send loudness rating (SLR) target difference value between a speakerphone SLR target value and a handset SLR target value.

14. The apparatus of claim 13 , wherein controlling the send output level includes amplifying the send output level of the transmit audio signal using automatic gain control if the send output level of the transmit audio signal is less than the send output level threshold value.

15. The apparatus of claim 14 , wherein amplifying the send output level of the transmit audio signal includes adding the difference between the send output level threshold value and the send output level of the transmit audio signal as a gain to the send output level of the transmit audio signal.

16. The apparatus of claim 13 , wherein controlling the send output level includes passing the transmit audio signal with substantially the same send output level if the send output level of the transmit audio signal is greater than or equal to the send output level threshold value.

17. The apparatus of claim 13 , wherein if the speakerphone is in a handset mode, the send output level of the transmit audio signal remains substantially the same.