Bring to the foreground when receiving: A user may switch to other apps when not using Zello. When someone contacts the user, this option brings the Zello app to the foreground.

Turn display on when receiving: In order for this setting to work, Bring to the foreground when receiving must be on. This will turn the screen on when a message is received.

Automatically activate a contact: Automatically brings the user to the talk screen for a given contact when a message from them comes in.

Bring to the foreground when push-to-talk button is pressed: Toggle on or off. When you are using a hardware device with an external PTT button, toggling this setting “on” will automatically bring Zello to the foreground when the external PTT button is pressed. 

Hardware knob mode: Only applicable to network radios or other devices with external knobs that are used for channel selection. This setting gives you a dropdown list of options that the knob will show you: 

• Contacts
• Channels
• Recents
• Indexed Contacts

Remove user account info from device on exit: When this setting is toggled on, the android devices in your network will not store user login information when the user exits the Zello app. This prevents sign-in credentials from being stored on a shared device after the user exits Zello. Learn more. Note that this is different from Shared Device functionality, which allows multiple shift workers to utilize the same Zello Work user. 

Notify about all unanswered calls: Toggle on to show a missed message badge for all incoming messages which have not been answered.

Automatically connect channels: Toggle on to connect the user to all channels as soon as they sign in. Only applicable to channels from which the user can disconnect. Learn more

Sort channels by status: Toggle on to place connected channels at the top of the Channels list, and disconnected channels at the bottom. When toggled off, channels are sorted alphabetically.

Font Size Boost: Allows you to increase the size of font in the Zello app for all Android users. Note that selecting an option for this from the console will prevent users from customizing it on their own devices. 

Recording amplifier (dB)*: Move the slider to the left to make outgoing audio softer or to the right to make outgoing audio louder.

Recording automatic gain control (beta): When toggled on, this overrides the Recording amplifier setting.

Increase volume on incoming message after inactivity (beta): Automatically increases the volume of an incoming message after 10 minutes of inactivity. Helps your users avoid missing messages

Playback amplifier (dB)*: Move the slider to the left to make incoming audio softer or to the right to make incoming audio louder.

Playback automatic gain control (beta): When active, this overrides Playback amplifier setting.

Noise suppression: Reduce background noise when recording.

PTT key code override:

Headset sequence mode:

Use specialized wired PTT speaker-mic or headset:

Use Bluetooth Classic (SPP) for the AINA Voice Responder button:

Wake the device to keep Zello connected: Prevents Zello from shutting off when in the background. Toggling off this setting will disable the keep-alive interval. 

Keep-alive interval (mobile)*: This is the polling time between the app and the service. A longer time polling time uses less bandwidth and improves battery life for those using the Android device. A shorter polling time keeps the user status display current and may improve connectivity. For most users, the default value should work fine. Options are s for seconds and m for minutes.

Use TCP only (mobile)*: Speeds sign in and improves cellular connection reliability. However, it may delay receiving messages in real-time. The alternative is TCP and UDP connectivity. Learn more here. 

Keep-alive interval (WiFi)*: This is the polling time between the app and Wi-Fi. A longer time polling time uses less bandwidth and improves battery life for those using the Android. A shorter polling time keeps the user status display current and may improve connectivity. For most users, the default value should work fine. Options are s for seconds and m for minutes.

Use TCP only (WiFi)*: Speeds sign-in and improves Wi-Fi connection reliability. However, it may delay receiving messages in real-time. The alternative is TCP and UDP connectivity. Learn more here. 

Status lockdown: Prevents users from turning off "Available" status. Learn more about Zello status here. 

Remove the Exit option from app menu: Prevents users from exiting the app and going into standby status. Use this in addition to Status lockdown to keep users in Available status.

Hide on inactivity: Minimizes the Zello app if it has been inactive for the selected length of time. Choose a length of time between six and sixty seconds, or Never to disable the feature. This does not log the user off, but the app will simply disappear from the foreground. 

Location sharing: Allows users to send their current location to another contact. The user’s location can still be seen in the management console if this is toggled off. 

Auto-run on startup: The Zello app starts automatically when the device is turned on. 

Set Zello status to Busy when phone is in silent mode: Automatically changes status to Busy when the user puts the phone in silent mode. This will prevent new messages from playing aloud. 

Allow messages playback during phone call: When toggled on, messages will play aloud while the user is in phone calls. 

Disable per user volume adjustment: When toggled on, prevents users from adjusting message volume for individual contacts. Learn more.

Disable option to mute selected users and channels: When toggled on, prevents users from muting other users and channels.

Playback buffer:

Allow overlay buttons: When toggled on, Android users can generate a talk button that allows them to send audio messages to a specific channel or contact while Zello is in the background. Learn more.

Allow extended notification in the Android system tray: When turned on, the Zello notification bar will show the last contact and allow the user to send a message directly from the pull-down notifications menu: 

Call pre-setup: Allows faster call setup for repeated calls to the same contact. Uses more data.

Asynchronous message delivery: Queues missed messages while in 'Standby' status and autoplays once the Internet connection is back and status is 'Available'.

Debug log size: Adjusts the amount of memory reserved for the application's debug log. Set to Large to store 10 times as many log messages. Note that you will not need to change this setting unless requested by the Zello team during troubleshooting. 

Use these settings to control the storage capacity for Zello messages on your Android devices. If you are worried about storage space on your Android devices, choose lower parameters to take up less space. Once your device reaches its storage limit, the oldest messages will be deleted. 

Automatically delete messages: Applies to message history stored on user devices. Note: Doesn't affect Message Vault storage. 

Protect history: When toggled on, prevents users from deleting message history on Android devices running Zello.

Maximum voice history size: A dropdown menu that allows you to select the storage capacity that Zello voice messages are allowed to take up on the users’ devices. Choose a value between 16 Mb and 1 Gb. 

Maximum number of images in the history: A dropdown menu. Choose a value between 100 and 10,000. 

Maximum number of call alerts in the history: A dropdown menu. Choose a value between 100 and 10,000. 

Maximum number of text messages in the history: Enter any value to control the max number of text messages stored on the users’ devices. Please note that zero is not a valid entry, and will not delete all text messages or prevent users from sending them. If you want to turn off the users’ ability to send text messages within your network, this is possible from the Common Settings menu. 

Maximum number of locations in the history: Enter any value to control the max number of locations stored on the users’ devices. Please note that zero is not a valid entry, and will not delete all location messages or prevent users from sending them. If you want to turn off the users’ ability to send location messages within your network, this is possible from the General - iOS and General - Android settings menus.

History playback auto-advance:  From the history screen of a conversation, all messages will be automatically played in order after the one that the user selected to play. Toggle off to only play a single message at a time.

Alerts

You can turn these alerts on or off. Configuring the settings in the management console prevents users from turning them on or off on their individual devices. However, users will be able to choose the alert tone from the app settings menu. 

Alert volume (beta): Choose a value between 0-100%. 

Ready to send beep (beta): Plays when the user presses the talk button to begin the message

Talk button-up beep (beta): Plays at the end of an outgoing message.

Delivery delayed beep (beta): Plays when the message is not able to be delivered immediately. Learn more

Incoming message beep: Plays at the beginning of an incoming voice message when the recipient’s status is Available. 

Incoming message beep while busy (beta): Plays at the beginning of an incoming voice message when the recipient’s status is Available. 

End of incoming message beep (beta): Plays at the end of an incoming voice message. 

Call alert beep: Plays when the user receives a Call Alert from an individual user. 

Default contact selected beep (beta): 

User text beep: Plays when the user receives a text from another user.

Channel text beep (beta): Plays when the user receives a text from within a channel.

Repeat call alert signal: Alerts user more than once when receiving a call. Select the number of times to repeat the alert from 1-20 or unlimited. 

Call alert repeat interval: Select the interval for a call alert being repeated between ten seconds and two minutes. 

Channel alert beep: Plays when the user receives a Call Alert from a channel. 

Repeat channel alert signal: Alerts user more than once when receiving a channel alert. Select the number of times to repeat the alert from 1-20 or unlimited. 

Channel alert repeat interval: Select the amount of time between a channel alert being repeated between ten seconds and two minutes. 

Image received beep: Plays when the user receives an image message. 

Location received beep (beta): Plays when the user receives a location message. 

New conversation beep: Plays when the user receives a message as part of a new conversation. Note: more new conversation settings can be found below. 

Connection lost beep (beta): Plays when the user becomes disconnected from the internet, resulting in a loss of connection to Zello. 

Connection restored beep (beta): Plays when internet connection has been restored. 

Error beep (beta):

Vibrate when ready to send (beta): Device vibrates at the beginning of an outgoing message. 

Vibrate on incoming message (beta): Device vibrates at the beginning of an incoming message. 

Vibrate on missed message (beta): 

New Conversation Notifications 

Enable new conversation notifications (beta): When enabled, notifications will include sound, vibration, and a visual notification anytime someone starts a new conversation with you.

New conversations timeout (beta): The amount of time that must pass in a channel or 1:1 interaction before considering an incoming message a "New Conversation"

 Sound (beta): Toggle on in order for users to receive an audio notification at the beginning of a new conversation. Users can modify the sound of the tone in their Zello app under Options > Notifications.

Vibration (beta): Toggle on in order for the user’s device to vibrate at the beginning of the conversation. 

Voice quality

Samples per second: It’s best to leave it as-is unless you’re familiar with this. This setting provides a dropdown menu that allows you to choose 8kHz, 16 kHz, 24kHz. This refers to the number of “samples” recorded every second - if you’re not familiar with this term, here is a straightforward explanation. A higher Sampling rate will produce higher quality transmission audio.  Refer to the Speex Codec manual for more information.                                                                 

Bitrate: It’s best to leave it as-is unless you’re familiar with this. A drop-down menu that allows you to choose Auto or 6,8,16,32,64,128 kbps. This refers to the amount of data used per second in sending an audio transmission. A lower bitrate will save data, but will produce lower-quality audio. Here is a more in-depth explanation. Refer to the Speex Codec manual for more information.                                  Frames per packet: The number of frames, or audio samples, per packet. [Frames per packet]*[Frame size] must be <= 120.

Frame size: The length of a sample in milliseconds. [Frames per packet]*[Frame size] must be <= 120.                                           

Jitter adjustment threshold (%): Jitter is audio packets getting lost or delayed during transmission. Jitter adjustment actively corrects for the effects of jitter to maintain audio quality. This setting controls the algorithm that adjusts jitter on Android devices in your network. Higher values reduce the chances of breaks in communication. Lower values reduce latency at the expense of increased probability of breaks in incoming messages.