This Frequently Asked Questions (FAQ) document provides a practical and user-focused overview of the GAC2500 Audio Conferencing Device. It is designed to help users understand the device’s core features, installation methods, operating modes, call handling, conferencing capabilities, and daily operations. The questions and answers are organized into clear categories and focus on common operational scenarios users may encounter when deploying or using the GAC2500 in professional conference environments. This document serves as a quick reference guide to support efficient setup, usage, and management of the device.
Product Overview & Hardware Basics
The GAC2500 is an enterprise-grade Android-based IP audio conference phone designed for professional meeting rooms. It supports high-quality audio conferencing, SIP calling, Android applications, and multiple connectivity modes, making it suitable for small to large conference environments.
The GAC2500 runs Android™ 4.4, allowing full access to compatible Android applications, including conferencing and productivity apps available from the Google Play Store and GS Market.
The device supports up to 6 independent SIP accounts, allowing multiple registrations for flexible calling and conferencing scenarios.
It features a 4.3-inch capacitive touch screen with a resolution of 800 × 480, supporting gesture-based navigation, on-screen keyboard input, widgets, and customizable desktops.
The GAC2500 includes three built-in microphones with a 12-foot pickup range and one high-fidelity speaker with a 15-foot coverage range, delivering HD audio with a frequency range up to 18 kHz.
The device provides the following interfaces:
- RJ45 Ethernet port
- RJ48 port for daisy-chain (cascade) mode
- Micro-USB port (USB OTG, PC or GVC connection)
- 3.5 mm audio interface
- 12V DC power port
- Reset pin for reboot, firmware update, or factory reset
The GAC2500 can be powered using:
- PoE+ (Power over Ethernet).
- 12V DC power adapter (included in the package).
The device supports multiple network and device connectivity options, including:
- Gigabit Ethernet
- Integrated Wi-Fi (2.4 GHz)
- Bluetooth
- USB
- 3.5 mm analog audio connection
Cascade mode allows two GAC2500 units to be connected via RJ48 CAT5 cable to extend microphone and speaker coverage for larger conference rooms. One unit acts as the master, and the other as the slave, with synchronized operation.
IP mode is recommended for rooms up to 3.6 m × 7.2 m, where a single GAC2500 can provide optimal audio pickup and coverage.
Cascade mode is recommended for rooms up to 7.2 m × 12.2 m, with a minimum distance of 5 meters between the two GAC2500 units for best audio performance.
The standard package includes:
- GAC2500 main unit
- 12V power adapter
- Ethernet cable
- Micro-USB cable
- RJ48 CAT5 cable
- Simplified Quick Installation Guide
- Certification Regulatory Paper
Installation, Power & Operating Modes
To power on the GAC2500, connect either a PoE-enabled Ethernet cable to the LAN port or plug in the 12V DC power adapter into the power supply interface. Once powered, the device will boot automatically and display the Android home (dial) screen.
IP Mode allows the GAC2500 to function as a standalone IP conference phone using SIP accounts. In this mode, the device connects directly to the network and supports calling, conferencing, scheduling, and Android applications. It is recommended for rooms 3.6 m × 7.2 m or smaller.
To configure IP Mode:
- Connect the LAN port to the network using an Ethernet cable.
- Power on the device using PoE or the power adapter.
- Once booted, the GAC2500 operates independently and can register SIP accounts for calls and conferences.
USB Slave Mode allows the GAC2500 to function as an audio input/output device for a PC or GVC3200. In this mode, conference and SIP features are disabled, and the GAC2500 acts purely as an audio peripheral for pickup and playback.
To use USB Slave Mode:
- Connect the Micro-USB port on the GAC2500 to a PC or GVC3200 using the USB cable.
- Power on the device using the power adapter.
- The screen will switch to USB Slave Mode interface automatically.
In most cases, the PC continues to use its default audio output device. To resolve this, manually set the GAC2500 as the default audio input and output device in the PC’s sound settings.
To configure Cascade Mode:
- Connect both GAC2500 units to the network via Ethernet.
- Connect the two devices using an RJ48 CAT5 cable.
- Power on both devices.
- On startup, assign one device as Master and the other as Slave when prompted.
For proper Cascade Mode operation:
- The master device must be connected to the network.
- Maximum of two devices only.
- Devices should be placed at least 5 meters apart.
- Recommended room size is up to 7.2 m × 12.2 m.
Mobile Phone Mode allows the GAC2500 to connect to a mobile phone using a 3.5 mm audio cable, enabling the device to capture and play audio during mobile calls. The GAC2500 acts as an audio hub but cannot dial numbers directly in this mode.
To connect:
- Power on the GAC2500 and connect it to the network.
- Connect a 3.5 mm male-to-male audio cable from the mobile phone headset port to the GAC2500 audio interface.
- The device will automatically switch to the AUX call screen once connected.
When Mobile Phone Mode is enabled:
- Calls cannot be dialed from the GAC2500 keypad.
- The AUX line is treated as one call line or one conference participant.
- Unplugging the cable may cause call exceptions.
- Audio quality depends on the cable and the mobile phone model.
User Interface, Navigation & Device Interaction
By default, the GAC2500 home screen is the dial screen, where users can enter numbers, select accounts, start calls, or initiate conferences. The home screen can be customized by editing desktops and widgets.
To access the soft keys, swipe upward from the bottom of the screen. The soft keys include Volume Up, Volume Down, Back, Home, and Process Manager. They will hide automatically after a short period of inactivity.
The status bar, located at the top of the screen, displays system and call-related status icons such as network connectivity, Bluetooth, Wi-Fi, DND, voicemail, VPN, USB devices, and call states. Users can drag it down to view full notifications and quick toggles.
Drag the status bar downward to view notifications. Individual notifications can be swiped left or right to remove them, or users can tap the clear-all icon in the upper-right corner to remove all notifications at once.
The GAC2500 supports multiple touchscreen gestures, including tap, long press, slide, drag, pinch-to-zoom, spread, and double-tap, allowing intuitive navigation through menus, apps, and content.
The default on-screen keyboard is English, with support for multiple input languages. Users can switch languages via Settings → Language & Keyboard → Keyboard & Input Methods and toggle between lowercase, uppercase, numbers, and symbols directly from the keyboard.
Long-press on an empty area of the home screen, select Set Wallpaper, then choose from built-in wallpapers, photos from storage, or live wallpapers. The selected wallpaper will apply immediately after confirmation.
Users can add up to 15 desktops by entering Edit Desktop mode and sliding to the last screen to add a new one. Desktops without widgets or shortcuts can be deleted using the delete icon in the preview screen.
From the idle screen, long-press a blank area and select Edit Desktop. Browse available widgets or shortcuts, then press and drag the desired item onto the selected desktop, ensuring sufficient space is available.
No. System applications cannot be deleted. However, users can remove shortcuts or widgets from the desktop without uninstalling the application itself.
The Process Manager displays all currently running applications. Users can swipe left or right to close individual apps or tap the close-all option to stop all running applications at once, helping manage system performance.
The LED indicator provides visual alerts:
Blue:
- Fast Flashing: Incoming call (including calls when conferencing and when phone is busy).
- Solid: Calling, Talking, Conferencing, Screensaver status.
- Slow Flashing: Call on hold.
Orange:
- Slow Flashing : Unhandled events. Including missed call (s), new voicemail (s), new SIP message (s).
- Solid : High memory usage, full message box, full contacts storage, network disconnection.
- Rapid Flashing : Upgrading.
None :
- OFF: Normal.
Calling Features, Call Handling & Conference Control
A Direct IP Call allows two VoIP devices to communicate without a SIP proxy server. Calls can be made when both devices are on the same LAN/VPN, have public IP addresses, or NAT is disabled. The IP address and port are entered using * for dots and # for colons.
From the home (dial) screen, select the desired account and call mode, enter the phone number using the keypad or on-screen keyboard, then tap the Dial button to place the call. Matching contacts and call history entries are suggested automatically while typing.
Redial allows users to call the last dialed number. From the dial screen, press the Dial button or the “#” key (if configured) when no digits are entered. Redial is only available if call history exists.
Yes. Users can dial calls directly from:
- Contacts by selecting an entry and tapping the dial icon.
- Call History by choosing a previous call record and dialing it.
Multiple contacts can also be selected to start a conference.
When an incoming call is received, the call screen appears. Users can tap Answer to accept the call or Reject to decline it. During an active call, incoming calls trigger a call-waiting tone and on-screen prompt.
Yes. When Quick Reply is enabled in the Notices settings, users can reject an incoming call by selecting a predefined SMS response, which is sent to the caller upon rejection (service provider support required).
During an active call, users can:
- Mute or unmute audio
- Hold or resume the call
- Adjust volume
- Start or stop call recording
- Add another call or start a conference
- Access additional options via the More menu
Tapping Hold places the current call on hold, allowing the user to make or receive another call. Tapping UnHold resumes the call. Calls can also be ended directly from the hold state.
The GAC2500 supports Blind Transfer and Attended Transfer:
- Blind Transfer sends the call directly to another number without consultation
- Attended Transfer allows the user to speak with the target party before completing the transfer
Both methods are accessible during an active call via the Transfer option.
When DND is enabled, all incoming calls are blocked without ringing. Blocked calls are still recorded in call history, and the DND icon appears in the status bar. Active calls are not affected.
The GAC2500 supports up to 7-way audio conferencing, including the host. The device can initiate conferences or join existing ones as a participant.
Conference hosts can:
- Mute or block individual participants
- Mute or block all participants
- Hold or remove participants
- View conference details (codec, SRTP)
- Lock or unlock the conference
- Start or stop recording
- End the entire conference session
Scheduling, Contacts, Applications & System Utilities
Users can schedule conferences from the Schedule application on the desktop. By tapping Add Conference, users can define the conference name, participants, date, start time, duration, reminder settings, and whether the conference should start automatically.
When the scheduled time approaches, the GAC2500 displays a reminder prompt. If Auto Conference is enabled, the device automatically initiates the conference. Otherwise, users are prompted to confirm whether to start the conference manually.
Yes. Users can edit scheduled conferences by selecting the entry in the Schedule list and tapping Edit. Conferences that have already occurred can be rescheduled from the History section using the reschedule option.
Scheduled or historical conferences can be deleted by:
- Long-pressing a conference entry and deleting it.
- Swiping left on a history entry to delete a single conference.
- Selecting multiple conferences for batch deletion.
Yes. Users can link a Google account and schedule conferences through Google Calendar. Conference members are added using a specific number format in the event description, and events synchronize with the GAC2500 Schedule app.
When a new voicemail is available, a voicemail icon appears in the status bar. Users can access voicemail by dialing the configured voicemail access number or opening the Voicemail application, then following the IVR prompts.
The GAC2500 can store up to 2,000 local contact entries, including names and phone numbers. Storage status can be viewed directly within the Contacts application.
Contacts can be:
- Imported from USB or storage devices.
- Downloaded from a server using TFTP, HTTP, or HTTPS.
Supported formats include XML, CSV, and vCard, with options to clear old contacts or replace duplicates.
Yes. The GAC2500 supports LDAP directory integration, allowing users to search and dial contacts from an LDAP server after configuring connection parameters such as server address, base DN, credentials, and attributes.
The blacklist allows users to block calls from specific numbers without affecting normal call handling. Blocked calls can be logged, notifications can be enabled, and blocking can be scheduled based on time settings.
Yes. The GAC2500 supports Android applications such as Skype for Business™ and Google Hangouts™. Once installed and signed in, calls from these apps can be added to ongoing conferences, subject to application compatibility.
Using the reset pin on the back of the device:
- Short press reboots the device
- Press for 4–9 seconds during power-up triggers firmware update from USB
- Press for more than 10 seconds during power-up restores factory settings