3.10 Sidetone (handset and headset MS)

3GPP43.050Release 17Transmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) systemTS

3.10.1 Sidetone loss

A sidetone requirement is appropriate for MSs using handsets and headsets. There are separate requirements for listener sidetone (LSTR) and talker sidetone (STMR). The listener sidetone performance is considered as the major parameter affecting the user perception of the system. Though talker sidetone is important to give the user some comfort in using the equipment.

3.10.1.1 LSTR

There is no explicit requirement on LSTR, since the requirements on ambient noise rejection in combination with the requirement on STMR should suffice to ensure acceptable LSTR.

3.10.1.2 STMR

For a dual mode GSM/3GPP telephone as well as for a single mode GSM MS the Side Tone Masking Rate (STMR) shall be as specified in [49] 3GPP TS 26.131.

Where a user‑controlled receiving volume control is provided, the STMR shall meet the requirement given above at the setting where the RLR is equal to the nominal value.

It is recommended that the STMR is independent of the volume control.

For a dual mode GSM/3GPP telephone compliance shall be checked according to the procedures described in [50] 3GPP TS 26.132.

For a single mode GSM MS conformance shall be checked according to the procedures described in [51] 3GPP TS 51.010.

3.10.2 Sidetone distortion

The requirement on sidetone distortion is applicable to single mode GSM MS only.

The third harmonic distortion generated by the terminal equipment shall not be greater than 10 %. Compliance shall be checked by the relevant procedures in [51] 3GPP TS 51.010.