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Jonathan CochranSep 1, 2025
What to do if the phone screen appears blank on my Cisco 7975G IP Phone?
- TTammy Peterson MDSep 1, 2025
To wake the touchscreen, try pressing it, lifting the handset, or pressing any button.
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What to do if the phone screen appears blank on my Cisco 7975G IP Phone?
To wake the touchscreen, try pressing it, lifting the handset, or pressing any button.
Why does my Cisco 7975G IP Phone keep resetting unexpectedly?
Your Cisco Unified IP Phone might be resetting due to several reasons. First, ensure the Ethernet connection is active, checking for port, switch, or cable issues. If voice network problems exist, investigate them. Confirm that the phone is properly configured for DHCP and that the DHCP server is correctly set up with a lease duration Cisco recommends to be 8 days. If a static IP address is used, verify its settings. Heavy network usage without a voice VLAN, unauthorized resets by other administrators, or DNS/connectivity errors could also be the cause. As a troubleshooting step, you can use the Erase softkey to reset the phone to its default values or power cycle the phone.
What to do if Cisco Unified IP Phone resets unexpectedly?
If your Cisco Unified IP Phone is unexpectedly resetting, several factors could be at play. First, check the Ethernet connection to ensure it's active and that there are no cable breaks. It's also worth investigating whether intermittent network outages are affecting voice traffic. Make sure the phone is properly configured to use DHCP, or if a static IP address is assigned, verify the settings are correct. Isolating the phones on a separate auxiliary VLAN may also improve voice traffic quality. To see if the phone received a reset command from Cisco Unified Communications Manager, press the Applications Menu button, then go to Settings > Status > Network Statistics. Look for 'Reset-Reset' or 'Reset-Restart' messages.
What to do if Cisco 7975G IP Phone cannot obtain a DHCP-assigned IP address after a factory reset?
If your Cisco IP Phone cannot obtain a DHCP-assigned IP address, and these errors typically indicate that the phone has completed a factory reset while 802.1X was enabled, then temporarily disable 802.1X authentication on the switch. Alternatively, temporarily move the phone to a network environment that is not using 802.1X authentication. Once the phone starts up normally in one of these conditions, you can access the 802.1X configuration menus and re-enter the shared secret.
Why does my Cisco IP Phone screen appear blank?
If the screen on your Cisco IP Phone appears blank but the Display button is lit, the phone is powered down (sleeping) to save energy. The phone will power up (wake) when the system sends the wake up message. You cannot wake the phone before its scheduled power up time. To wake up the phone plug in the power adapter. Unplugging and plugging it back in will not wake up the phone while it is sleeping.
What to do if softkey is missing on Cisco 7975G IP Phone?
If you see a 'Missing Softkey' on your Cisco IP Phone, there might be additional softkeys to display. Press the More button to reveal them. The state of the line determines the phone softkeys, so try changing the line state (for example, go off-hook or have a connected call). If the issue persists, your phone may not be configured to support the feature associated with that softkey. In this case, contact your system administrator to request access to the feature.
Why can't I hear a dial tone on my Cisco IP Phone?
If you cannot hear a dial tone or complete a call on your Cisco IP Phone, it might be because you need to log into the Extension Mobility service. Alternatively, you may need to enter a client matter code (CMC) or forced authorization code (FAC) after dialing a number, if you are using an SCCP phone. It is also possible that time-of-day restrictions prevent you from using some features during certain hours.
What to do if softkey does not appear on Cisco 7975G IP Phone?
If a softkey that you want to use does not appear on your Cisco IP Phone, press the 'more' button to reveal additional softkeys. You might also need to change the line state, for example, by going off-hook or having a connected call. Additionally, your phone might not be configured to support the feature associated with that softkey.
What to do if the Settings button is unresponsive on my Cisco 7975G IP Phone?
If the Settings button is unresponsive, your system administrator might have disabled it on your phone.
Why does Barge fail and result in a fast busy tone on my Cisco 7975G?
Barge fails and results in a fast busy tone because you cannot barge an encrypted call if the phone you are using is not configured for encryption.
General| Handset type | Wired handset |
|---|---|
| Product type | IP Phone |
| Product color | Grey, Silver |
| Speakerphone | Yes |
| Voice codecs | G.711Mu, G.711a, G.722, G.729A, iLBC |
| Number of melodies | 24 |
| Aspect ratio | 4:3 |
| Display diagonal | 5.6 \ |
| Display resolution | 320 x 240 pixels |
| Lines quantity | 8 lines |
| Phonebook capacity | - entries |
| Number of VoIP accounts | - |
| Front camera | No |
| Security algorithms | 128-bit AES |
| Networking standards | IEEE 802.1Q, IEEE 802.1p, IEEE 802.1x, IEEE 802.3af |
| Ethernet LAN data rates | 10, 100, 1000 Mbit/s |
| Ethernet LAN interface type | Gigabit Ethernet |
| Supported network protocols | DHCP, TFTP |
| Volume control | Digital |
| Headphone outputs | 1 |
| Ethernet LAN (RJ-45) ports | 2 |
| Number of handles included | 1 pc(s) |
| AC adapter output voltage | 48 V |
| Storage temperature (T-T) | -10 - 60 °C |
| Operating temperature (T-T) | 0 - 40 °C |
| Operating relative humidity (H-H) | 10 - 95 % |
| Certification | FCC |
Weight and Dimensions| Depth | 152.4 mm |
|---|---|
| Width | 266.7 mm |
| Height | 203.2 mm |
| Weight | 1600 g |
