Callsign

Callsign (Package Name: jp.csl.callsign) is developed by Sony Business Solutions Corporation and the latest version of Callsign 1.4.4 was updated on June 14, 2025. Callsign is in the category of Communication. You can check all apps from the developer of Callsign. Currently this app is for free. This app can be downloaded on Android 7.0+ on APKFab or Google Play. All APK/XAPK files on APKFab.com are original and 100% safe with fast download.

This is a commercial radio device (transceiver/intercom) for corporate users that uses an IP network. Using a smartphone, you can operate it in the same way as a dedicated device.
■Main features
・Connect anywhere
Conventional wireless devices have limitations on connection distance, but they can be used anywhere with an internet connection such as 3G/4G/5G/Wi-Fi.
・Join 6 groups with one smartphone
There is no need to carry multiple smartphones when using communication networks for the whole group and small groups, or when a leader is responsible for multiple sites. You can also choose where to send the conversation.
・Unlimited number of devices to connect
Since there are no frequency restrictions, there is no limit to the number of smartphones that can be connected.
・High sound quality & low delay
Sony's proprietary audio algorithms, such as the "Intelligent Noise Filter" that separates ambient noise such as wind noise and the sound of cars running, leaving only the human voice, provide clear feedback control, noise cancellation, low latency measures, and audio MIX. It achieves improved sound quality and reduced communication traffic.
・Linkage with existing intercom system
By linking via an interface unit (separate arrangement required), it is possible to effectively utilize existing systems.
・PTT operation function using voice recognition
Sony's unique voice recognition technology allows PTT operation by voice. You can enter a call state by saying "PTT-on", "mic on", and "conversation on" into the microphone of your smartphone or earphone.
・Individual call function
You can make one-on-one calls with specified devices.
・Group call function
This function allows you to send a request to a group to respond to an individual call. The response request will be notified to all devices participating in the group, and an individual call will be started with the first device in the group that responds.
Note: A subscription is required to use all features. To apply for a contract, please apply from the product web page below.
■About location information
Depending on the type of contract, there is a function that sends the location information of the app being used to the server, and if the user enables it, the administrator can check the location information of the app on a map using dedicated software.
■About functional limitations (features that can be used free of charge)
・Number of connected devices: Up to 5 devices
・Number of simultaneous users: 1 group only
・Conversation transmission time: Total up to 10 minutes/hour/per device
・Individual call function: Not possible
・Group call: Not possible
・Web management function: None
・Specification of connection server: Cannot be specified
■Product web page
https://www.sony.jp/professional/solution/callsign/index.html
■Various manuals
https://www.sony.jp/professional/solution/callsign/documents/
■Video manual (YouTube)
Basic operation of the app: https://youtu.be/dFagZVFjW6o
Management screen basic operations (paid function): https://youtu.be/jgQ7oKAlDCA
■About inquiries
We do not accept inquiries from customers using free features. If you have a contract or are considering a contract, please contact your service provider.
Regarding vulnerability information regarding this application and service, please refer to
Please contact the vulnerability reporting desk "SECURE@SONY": https://secure.sony.net/.
■Notes
- Although we have confirmed that it works correctly with certain smartphones, we do not guarantee that it will work with your smartphone. Please test it before use.
・Data communication charges incurred when downloading and using this app will be borne by the customer.
-Services provided free of charge are subject to change or cancellation without notice.

Callsign 1.4.4 Update

・インテリジェントノイズフィルターの音質改善
・オープンスピーカー対応
・細かい不具合の修正