In general, you will be adjusting the various gain settings on the device. The actual setting varies depending on the Sipura. Some general guidelines:

1. Valid range is -16 (quiet) to 12 (loud) and is in dB.
2. A 6 dB adjustment doubles (or halves) the volume.

On the SPA-841, there is a volume adjustment to hear the remote end. This can be accessed by pushing the "triangle" button and using the up/down arrows. Alternatively, you can adjust this on the Phone tab under Handset, Headset, or Speakerphone volume. If others cannot hear you, look on the Phone tab. Adjust the Input Gain of the Handset, Headset, or Speakerphone as appropriate.

On the SPA3000 FXO (PSTN) port, there are specific parameters you will have to adjust under the PSTN Line tab:

SPA To PSTN Gain
PSTN To SPA Gain
FXO Port Impedance: (if the PSTN line is outside US/Canada)

On the other SPAs, including the SPA3000 FXS ports, under the Regional tab, adjust the following parameters:

FXS Port Input Gain:
FXS Port Output Gain:
FXS Port Impedance: (if you use a non-US telephone)