Mute during call
To mute the microphone during a call, press the soft-
key labeled “Mute”. To switch the microphone back on
again, press the “Mute” key again. The current status is
shown in the display with the Mute/Unmute Icon.
Secure Push to Talk
In certain situations, especially when you have a lot of
background noise or need a high speaker volume, you
can activate the Push to Talk mode (or PTT for short),
to achieve good call results. This can be done either
during a Secure Call or before. To activate or deactivate
PTT, press the “Menu” Softkey, choose “Push to Talk”
in the Settings screen, toggle the setting with the center
click and press the Done softkey to return to the main
screen. PTT works like a two-way radio. When you
want to talk, you press the PTT button. When you fin-
shed speaking, you release the button. The button used
for PTT on your CryptoPhone G10 is the Camera but-
ton on the right side of the device. Please do not forget
to release the talk button when you finished talking.
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Secure Calls while moving
When using the GSMK CryptoPhone while moving
fast in a car or a train, you may experience a degrada-
tion in call sound quality, periods of longer delay and
short dropouts during a call. These effects are the result
of a so called handover that occurs when you move
from the coverage zone of one GSM tower (also called
'GSM cell') to the next. During the handover the data
connection is briefly interrupted. To prevent important
call contents from getting lost, the GSMK Crypto-
Phone, unlike other encrypted voice systems, acceler-
ates the speed of decoding for a moment after the
dropout, to catch up with the lost transmission time.
This results in the voice of your partner rising in pitch
(the »Mickey Mouse effect«) for a moment. After a
short time the pitch returns to normal. The GSMK
CryptoPhone G10 has been successfully tested travel-
ing at speeds of up to 180km/h. The frequency and
intensity of disturbances is primarily determined by the
GSM network. In rural areas, the network consists of
fewer and bigger cells, resulting in less frequent han-
dovers and less disturbances. In urban areas the net-
work has typically a high density of small cells, result-
ing in many handovers when moving and thereby
causing more disturbances.
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