To initiate a call with the speakerphone, issue: AT#CLS=8 AT#VRN=0 AT#VLS=6 (Selects the speakerphone) It is recommended to set the VRN command to 0 which disables ringback detection before reporting the VCON message. ATDT<number> The modem then responds with: VCON (based on the AT#VRA and #VRN setting) Additional DTMF (for example in a voice mail application) can be entered by issuing: AT#VTS=<digit> When DTMF digits are sent, it is recommended that the default value of the tone length be changed to 100 ms using the command #VBT: AT#VBT=1 The call can be transferred (PBX function) by entering the flash dial modifier (AT#VTS=!). Terminate the call with: ATHthe #VLS is the key here. 9 different settings for source of audio.