Product Support
Welcome to Product Support. Enter your model number to retrieve manuals, frequently asked questions (FAQs), troubleshooting tips, and additional resources.
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Turn over the base of your product to locate the model number as illustrated in the image below.
5.8 GHz expandable cordless phone with digital answering s
MI6879
Manuals & Documentation
Frequently Asked Questions
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For message recording, your telephone has a Built-in answering system, and it also supports Voicemail service offered by your telephone service provider(subscription is required, and fee may apply).
The main differences between them are:
BUILT-IN ANSWERING SYSTEM VOICEMAIL SERVICE SUPPORTED BY Telephone system Telephone service provider SUBSCRIPTION No Yes FEES No May apply ANSWER INCOMING CALLS •After 3 rings by default.
•It can be changed via handset or the telephone base menu.•Usually after 2 rings.
•It can be changed by contacting your telephone service providerSTORAGE Telephone base Server or System DISPLAY NEW MESSAGE • Handset - XX new messages
• Telephone base - XX new messages• Handset - 
and New voicemail
• Telephone base -
RETRIEVE MESSAGES • Press PLAY/STOP on the telephone base; OR
• Press MENU, and then select Play messages on the handset; OR
•Access remotely with an access code• Press 
on the dialpad, and enter an access number from your telephone service provider.Based on the above information, if you want to...
Use the built-in answering system to record your messages
Your Voicemail service can bundle in your telephone plan. As such, you would need to contact your telephone service provider to disable it.
*TIP: Can I switch back to Voicemail service if I want to?
As long as your telephone plan includes the Voicemail service, you can still re-enable it through your service provider.Use the voicemail service to record your messages
Simply turn off the Built-in answering system at any time, and you can use the Voicemail service only.Use both the Built-in answering system and the Voicemail service to record messages
By default, the Voicemail service is usually set to answer after 2 rings, while your Built-in answering system is set after 3 rings. Please check with your telephone service provider to learn how to set your voicemail settings.Suggest to set your Built-in answering system to answer calls at least 2 rings earlier than your Voicemail service. In other words, if your answering system sets to answer after 3 rings (by default), then you need to set the Voicemail service to answer after 5 rings.
What happened is that if you on a call or the answering system is already recording, and you receive ANOTHER incoming call, then the third caller is able to leave a Voicemail message.
On the other hand, if you are not on a call nor the answering system is recording, the incoming caller can leave a message directly to the Built-in Answering system.
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An A will appear in the display window when the Announce Only feature is turned on. In Announce Only mode, callers hear an announcement but cannot leave a message. If you want to receive messages, make sure Announce Only is turned off.
To turn Announcement Only mode on or off, please complete the following steps:
Step 1: Press SETUP four times, the system announces, Announcement only. Record no messages. To change the setting, press CHANGE.
Step 2: Press CHANGE until you hear the desired option (ON or OFF).
Step 3: Press TIME/SET to confirm your selection.
Step 4: Press PLAY/STOP to save and exit.
For more information on configuring Announce Only and other features of the answering system, please refer to the Answering System Operation section of the user manual.
My telephone handset appears to be dead. What should I do?
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Tip 1 of 3
If your handset responds in any way (beeps, displays a message on the screen, etc.) then it is not dead. Please review the Frequently Asked Questions list to check for a more specific symptom to your problem.
A common cause for dead handset symptoms is a dead battery. We recommend that you initially charge the handset battery for 16 hours. On average, this provides 5 hours of talk time and 6 days of standby. If the handset does not hold a charge or seems dead, we suggest the following:
• Please verify that the handset battery is securely plugged into the back of the handset.
• Check that there is power to the base and cradle. If there is power and the handset is placed face up, the CHARGE light on the base will be on.
• Place the handset in the cradle and charge it overnight, making sure that the dialpad is facing up.
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Tip 2 of 3
If the handset is not responding normally, you may need to reset your telephone system. Complete the following steps to reset the telephone system:
Step 1: Disconnect the power to the telephone base.
Step 2: Disconnect the handset battery.
Step 3: Wait a few minutes and then reconnect the power to the telephone base.
Step 4: Reconnect the handset battery
Step 5: Wait about one minute for the handset to re-establish a link with the telephone base and then test the phone again.
NOTE: After resetting the telephone system, you will need to reset the clock. If the time is not set, CL will be shown on the answering system’s display.
NOTE: If you have caller ID service, the time will automatically be updated whenever caller ID information is delivered. However, since caller ID delivers the date, rather than the day, you must program the year once so the system can derive the day of the week.
To set the day and time, confirm that the answering system is turned on and then complete the following steps:
Step 1: Press TIME/SET. The system will announce the current setting.
Step 2: Press TIME/SET again. The system will announce the current day setting.
Step 3: Press CHANGE on the base until you hear the correct day.
Step 4: Press TIME/SET. The system will announce the current hour setting.
Step 5: Press CHANGE on the base until you hear the correct hour.
Step 6: Press TIME/SET. The system will announce the current minute setting.
Step 7: Press CHANGE on the base until you hear the correct minute.
NOTE: Pressing and holding the CHANGE button when setting the day and time will increase the minutes or years by 10.
Step 8: Press TIME/SET. The system will announce the current year setting.
Step 9: Press CHANGE on the base until you hear the correct year.
Step 10: Press TIME/SET to confirm. The system will announce the new day and time setting followed by a confirmation beep. -
Tip 3 of 3
You may need to replace the rechargeable battery, especially if it has been in service for more than one year. To find a replacement, refer to our VTech Battery Finder. If a battery for your model is unavailable, you can search the internet using the key words cordless phone batteries for an on-line supplier. If you prefer to purchase locally, you can look for a replacement battery at your area consumer electronics retailers. It is recommended that you take your present battery with you to insure your replacement is the correct size and has the correct plug (where applicable) and specifications.
The handset displays UNABLE TO CALL TRY AGAIN. Why can’t I place a call?
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Tip 1 of 5
Move the handset closer to the base. The operating range may vary with environmental conditions and time of use. There may be places within your environment that a cordless phone will not work well. If the problem only occurs in certain areas of your environment, you can conclude that there is nothing wrong with the phone. Consider trying a phone that operates on a different wireless frequency. -
Tip 2 of 5
Other electronic products (i.e., 802.11 wireless networking products, radios, radio towers, pager towers, cell phones, intercoms, room monitors, televisions, personal computers, kitchen appliances and other cordless phones) can cause interference with your cordless phone. Try installing your phone as far away as possible from these types of electronic devices. -
Tip 3 of 5
Confirm proper installation of the telephone base power supply and handset battery. You should only use the VTech power supply provided with your telephone. Make sure the power supply is not connected to an electrical outlet that is controlled by a wall switch. Confirm that the electrical outlet that the telephone is plugged into is working. -
Tip 4 of 5
If the handset is not responding normally, you may need to reset your telephone system. Complete the following steps to reset the telephone system:
Step 1: Disconnect the power to the telephone base.
Step 2: Disconnect the handset battery.
Step 3: Wait a few minutes and then reconnect the power to the telephone base.
Step 4: Reconnect the handset battery
Step 5: Wait about one minute for the handset to re-establish a link with the telephone base and then test the phone again.
NOTE: After resetting the telephone system, you will need to reset the clock. If the time is not set, CL will be shown on the answering system’s display.
NOTE: If you have caller ID service, the time will automatically be updated whenever caller ID information is delivered. However, since caller ID delivers the date, rather than the day, you must program the year once so the system can derive the day of the week.
To set the day and time, confirm that the answering system is turned on and then complete the following steps:
Step 1: Press TIME/SET. The system will announce the current setting.
Step 2: Press TIME/SET again. The system will announce the current day setting.
Step 3: Press CHANGE on the base until you hear the correct day.
Step 4: Press TIME/SET. The system will announce the current hour setting.
Step 5: Press CHANGE on the base until you hear the correct hour.
Step 6: Press TIME/SET. The system will announce the current minute setting.
Step 7: Press CHANGE on the base until you hear the correct minute.
NOTE: Pressing and holding the CHANGE button when setting the day and time will increase the minutes or years by 10.
Step 8: Press TIME/SET. The system will announce the current year setting.
Step 9: Press CHANGE on the base until you hear the correct year.
Step 10: Press TIME/SET to confirm. The system will announce the new day and time setting followed by a confirmation beep. -
Tip 5 of 5
First, deregister ALL handsets:
Step 1: Press and hold FIND HANDSET on the main telephone base for 10 seconds.
Step 2: When the IN USE light starts to flash, release the FIND HANDSET button.
Step 3: Press and release FIND HANDSET again. The IN USE light will turn off and in a few seconds, all handsets will be de-registered.
Step 4: All handsets will show NOT REGISTERED.
Now, register all handsets (1 handset at a time):
Step 1: Place the handset in the base unit or a charger that is connected to a power outlet. If PRESS FIND HNDST 4 SEC ON BASE does not appear on the screen after a few seconds, lift up handset and place in base or charger again.
Step 2: On the telephone base, press and hold FIND HANDSET for four seconds. Release FIND HANDSET once the IN USE light comes on.
After a while the handset will emit a series of tones, the newly registered handset will be assigned the lowest extension number not previously assigned to another system handset (1-4) when successfully registered. Repeat Steps 1 and 2 if the handset does not successfully register to the telephone base within two minutes.
REPEAT THE REGISTRATION PROCEDURE FOR EACH SYSTEM HANDSET.
How do I clear the caller ID memory?
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To delete all caller ID records when you are reviewing the call log, press and hold REMOVE. The screen will display DELETE ALL CALLS? Press SEL to confirm. Press OFF to return to the call log record previously displayed.
NOTE: You cannot delete "all" calls if there are new calls in the call log. Please view the call log and then try to delete all calls.
When I talk on this phone, I hear an echo. Is there a way to reduce or eliminate this condition?
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This unit employs state-of-the-art frequency hopping spread spectrum (FHSS) technology to achieve one of the longest ranges in the consumer cordless telephone industry. FHSS is a digital technology that is also found in cellular telephones. Just as it is common to experience echo in
some cellular telephone systems, some users will experience occassional echo while using this phone. The presence and/or level of echo will depend on the electrical characteristics of the connection between the phone and the users local central office. This is normal operation.
Try lowering the volume on your handset to reduce the echo.
Why won’t the battery(s) in my telephone handset hold a charge?
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Tip 1 of 4
Place the handset face up in the charging base and confirm that the charge contacts on the handset and base are making a good connection. The CHARGE light on the telephone base will be on when the handset is charging.
You should allow 16 hours to fully charge the handset battery. For optimum daily performance, return the handset to its telephone base when not in use. -
Tip 2 of 4
Make sure you are using the battery supplied with your phone. If you are replacing the battery and you need assistance, refer to our VTech Battery Finder. If a battery for your model is unavailable, you can search the internet using the key words cordless phone batteries for an on-line supplier. If you prefer to purchase locally, you can look for a replacement battery at your area consumer electronics retailers. It is recommended that you take your present battery with you to insure your replacement is the correct size and has the correct plug (where applicable) and specifications. -
Tip 3 of 4
Recharge the handset more often for heavy use. A full charge provides an average of 7.5 hours of talk time and 3.5 days of standby. -
Tip 4 of 4
You may need to replace the rechargeable battery, especially if it has been in service for more than one year. To find a replacement, refer to our VTech Battery Finder. If a battery for your model is unavailable, you can search the internet using the key words cordless phone batteries for an on-line supplier. If you prefer to purchase locally, you can look for a replacement battery at your area consumer electronics retailers. It is recommended that you take your present battery with you to insure your replacement is the correct size and has the correct plug (where applicable) and specifications.
Why is WARNING CHECK BATTERY! shown on the handset display when I put it in the base?
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Tip 1 of 2
Confirm proper installation of the handset battery. If the battery is missing or installed wrong, you will see this error message. The proper installation procedure for the battery is as follows:
Step 1: Align the two holes in the plug with the socket pins, then snap the plug into place.
Step 2: Place the battery in the compartment with the wires in the upper left corner.
Step 3: Replace cover by sliding it upwards until it clicks into place.
Step 4: Be sure to charge the battery in the handset for a minimum of 16 hours before using your phone. -
Tip 2 of 2
You may need to replace the rechargeable battery, especially if it has been in service for more than one year. To find a replacement, refer to our VTech Battery Finder. If a battery for your model is unavailable, you can search the internet using the key words cordless phone batteries for an on-line supplier. If you prefer to purchase locally, you can look for a replacement battery at your area consumer electronics retailers. It is recommended that you take your present battery with you to insure your replacement is the correct size and has the correct plug (where applicable) and specifications.
The ringer on my phone is too loud or too soft. How do I adjust the ringer volume?
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To adjust the handset ringer volume, complete the following steps:
Step 1: With the handset in idle (off) mode, press MENU then press ▲ or ▼ until RINGER VOLUME is shown.
Step 2: Press SEL. You will hear a sample of the ringer.
Step 3: Press ▲, ▼, or a digit (0 through 6). You will hear a sample of the new ringer volume and the volume bar will be increased or decreased each time the setting is adjusted. Press SEL to confirm.
- OR -
Step 1: With the handset in idle (off) mode, press ▲ or ▼ of the volume control on the side of handset will directly go to ringer volume menu.
Step 2: Press ▲ or ▼ to adjust the ringer volume and the ringer volume will be saved automatically.
NOTE: The handset will not ring when a call comes in if ringer volume is at the lowest setting.
Why won’t the CHARGE light turn on when I place the handset in the base?
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Tip 1 of 6
Place the handset face up in the charging base and confirm that the charge contacts on the handset and base are making a good connection. The CHARGE light on the telephone base will be on when the handset is charging.
You should allow 16 hours to fully charge the handset battery. For optimum daily performance, return the handset to its telephone base when not in use. -
Tip 2 of 6
Confirm proper installation of the telephone base power supply and handset battery. You should only use the VTech power supply provided with your telephone. Make sure the power supply is not connected to an electrical outlet that is controlled by a wall switch. Confirm that the electrical outlet that the telephone is plugged into is working. -
Tip 3 of 6
Please make sure that the cords (power and telephone line) are plugged into the channels on the bottom of the base. If the cords are not properly installed, the base will not sit level and the phone may not charge properly. -
Tip 4 of 6
Make sure that the battery cover is properly secured on the handset. If the battery cover is not correctly installed, it may prevent the handset from charging. -
Tip 5 of 6
Dirty charge contacts on the telephone base and handset could prevent the batteries from charging. Clean the handset and base charge contacts using a pencil eraser or a cloth to eliminate deposit accumulation. -
Tip 6 of 6
If the handset is not responding normally, you may need to reset your telephone system. Complete the following steps to reset the telephone system:
Step 1: Disconnect the power to the telephone base.
Step 2: Disconnect the handset battery.
Step 3: Wait a few minutes and then reconnect the power to the telephone base.
Step 4: Reconnect the handset battery
Step 5: Wait about one minute for the handset to re-establish a link with the telephone base and then test the phone again.
NOTE: After resetting the telephone system, you will need to reset the clock. If the time is not set, CL will be shown on the answering system’s display.
NOTE: If you have caller ID service, the time will automatically be updated whenever caller ID information is delivered. However, since caller ID delivers the date, rather than the day, you must program the year once so the system can derive the day of the week.
To set the day and time, confirm that the answering system is turned on and then complete the following steps:
Step 1: Press TIME/SET. The system will announce the current setting.
Step 2: Press TIME/SET again. The system will announce the current day setting.
Step 3: Press CHANGE on the base until you hear the correct day.
Step 4: Press TIME/SET. The system will announce the current hour setting.
Step 5: Press CHANGE on the base until you hear the correct hour.
Step 6: Press TIME/SET. The system will announce the current minute setting.
Step 7: Press CHANGE on the base until you hear the correct minute.
NOTE: Pressing and holding the CHANGE button when setting the day and time will increase the minutes or years by 10.
Step 8: Press TIME/SET. The system will announce the current year setting.
Step 9: Press CHANGE on the base until you hear the correct year.
Step 10: Press TIME/SET to confirm. The system will announce the new day and time setting followed by a confirmation beep.
How do I register a new accessory handset to the base?
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When first purchased, all accessory handsets show NOT REGISTERED on the screen. To register a handset:
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Step 1: Place the handset in the base unit or a charger that is connected to a power outlet. If PRESS FIND HNDST 4 SEC ON BASE does not appear on the screen after a few seconds, lift up handset and place in base or charger again.
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Step 2: On the telephone base, press and hold FIND HANDSET for four seconds. Release FIND HANDSET once the IN USE light comes on.
After a while the handset will emit a series of tones, the newly registered handset will be assigned the lowest extension number not previously assigned to another system handset (1-4) when successfully registered. Repeat Steps 1 and 2 if the handset does not successfully register to the telephone base within two minutes.
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Tip 1 of 8
If you subscribe to DSL service for this telephone line, DSL filters must be plugged into EVERY phone jack that has a phone. The DSL signal can cause static/noise, squealing (similar to fax tones), caller ID disruption and other issues on your line. DSL filters block the high frequency DSL signals from being transmitted to the telephone. If you are not using the DSL filters provided by the telephone company, this will cause static/noise and possibly caller id issues on your phones.
In most cases, we recommend you connect the plug end of the DSL filter into the telephone jack, then connect a telephone cord between the filter and your phone.
Please contact your service provider to obtain DSL filters and installation information. -
Tip 2 of 8
Move the handset closer to the base. The operating range may vary with environmental conditions and time of use. There may be places within your environment that a cordless phone will not work well. If the problem only occurs in certain areas of your environment, you can conclude that there is nothing wrong with the phone. Consider trying a phone that operates on a different wireless frequency. -
Tip 3 of 8
To get better reception, try moving the telephone base to higher location. Relocate telephone base near a window if using telephone outside. -
Tip 4 of 8
Other electronic products (i.e., 802.11 wireless networking products, radios, radio towers, pager towers, cell phones, intercoms, room monitors, televisions, personal computers, kitchen appliances and other cordless phones) can cause interference with your cordless phone. Try installing your phone as far away as possible from these types of electronic devices. -
Tip 5 of 8
If your phone shares a power outlet with a modem, or if it is plugged in to a shared surge protector, try plugging the phone (or modem/surge protector) in at a different location. If this solves the problem, re-locate your phone or modem farther apart from one another, or use separate surge protectors. -
Tip 6 of 8
If you have connected this telephone to a phone jack that has not been used before, or that has not been used in sometime, there may be problems with this jack that you are not aware of. Use a telephone jack that you know is in proper working order. -
Tip 7 of 8
You may have a line problem. To test for a line problem, test your unit at another location such as your neighbor’s or relative’s house. If your unit works at another location, contact your local telephone company. -
Tip 8 of 8
There may be places within your environment that a cordless phone will not work well. If the problem only occurs in certain areas of your environment, there is nothing wrong with the phone. This is normal radio operation.
How do I set the day and time on my telephone ?
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During initial setup or after a power loss, you may need to set the time. If the time is not set, CL will be flashing in the base display window.
NOTE: If you have caller ID service, the time will automatically be updated whenever caller ID information is delivered. However, since caller ID delivers the date, rather than the day, you must program the year once so the system can derive the day of the week.
To set the day and time, complete the following steps:
Step 1: Press TIME/SET. The system will announce the current setting.
Step 2: Press TIME/SET again. The system will announce the current day setting.
Step 3: Press CHANGE on the base until you hear the correct day.
Step 4: Press TIME/SET. The system will announce the current hour setting.
Step 5: Press CHANGE on the base until you hear the correct hour.
Step 6: Press TIME/SET. The system will announce the current minute setting.
NOTE: Pressing and holding the CHANGE button when setting the day and time will increase the minutes or years by 10.
Step 7: Press CHANGE on the base until you hear the correct minute.
Step 8: Press TIME/SET. The system will announce the current year setting.
Step 9: Press CHANGE on the base until you hear the correct year.
Step 10: Press TIME/SET to confirm. The system will announce the new day and time setting followed by a confirmation beep.
Why am I not receiving caller ID on my phone?
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Caller ID and Call Waiting ID are subscription services, available from most local telephone service providers. You must subscribe to these services in order for the features to work on your phone. Contact your local telephone service provider for more information.
In addition, your caller must be calling from an area that supports caller ID.
Both you and your caller’s telephone service provider must use compatible caller ID systems.
If you subscribe to DSL service for this telephone line, DSL filters must be plugged into EVERY phone jack that has a phone. The DSL signal can cause caller ID disruption, static, noise and other issues on your line. DSL filters block the high frequency DSL signals from being transmitted to the telephone. If you are not using the DSL filters provided by the telephone company, this will cause static/noise and possibly caller id issues on your phones.
In most cases, we recommend you connect the plug end of the DSL filter into the telephone jack, then connect a telephone cord between the filter and your phone.
Please contact your service provider to obtain DSL filters and installation information.
Caller ID and Call Waiting ID may not be available for every call. Common reasons are incompatibilities between your and your caller’s service, transmission errors and answering calls before the ID data is received.
How can I improve the sound quality on my cordless phone?
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If your handset has a CHANNEL (or CHAN) button, press it in order to improve the sound quality. You may need to press the CHANNEL button more than once.
The handset may be out of range. Try moving closer to the base. The handset(s) and base can only communicate over a certain distance which can vary with their placement, the weather and the operating environment of your home/office.
If you subscribe to DSL service for this telephone line, DSL filters must be plugged into EVERY phone jack that has a phone. The DSL signal can cause static/noise, squealing (similar to fax tones), caller ID disruption and other issues on your line. DSL filters block the high frequency DSL signals from being transmitted to the telephone. If you are not using the DSL filters provided by the telephone company, this will cause static/noise and possibly caller id issues on your phones.
In most cases, we recommend you connect the plug end of the DSL filter into the telephone jack, then connect a telephone cord between the filter and your phone.
Please contact your service provider to obtain DSL filters and installation information.
A low battery pack may affect the sound quality. You may need to charge the handset. Also, try repositioning the handset against your ear until the sound quality improves.
Electronic products (i.e., 802.11 wireless networks, radios, radio and pager towers, cell phones, intercoms, room monitors, televisions, personal computers, kitchen appliances and other cordless phones) can cause interference with your cordless phone. Try installing your phone as far away as possible from these types of electronic devices.
Appliances or other cordless phones plugged into the same circuit as the telephone base can cause interference. Try moving the appliances or telephone base to another outlet.
Microwave ovens may operate on the same frequency as your telephone. You may experience static on your telephone while the microwave oven is operating. Do not install your cordless telephone in the same outlet or near the microwave oven.
Disconnect the telephone base from the modular jack and plug in a corded telephone. If calls are still not clear, the problem is probably in the wiring or local service. Contact your local service company (charges may apply).
If your phone shares a power outlet with a modem, or if it is plugged into a shared surged protector, try plugging in the phone (or modem/surge protector) at a different location. If this solves the problem, relocate your phone and modem farther apart from each other, or use separate surge protectors.
The layout of your home or office may be limiting the operating range. Try moving the base to another location, preferably a higher location for better reception. If your telephone base has an adjustable antenna, ensure it is pointing up.
Why is an A showing in the base message window?
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An A will appear in the display window when the Announce Only feature is turned on. In Announce Only mode, callers hear an announcement but cannot leave a message. If you want to receive messages, make sure Announce Only is turned off.
To turn Announcement Only mode on or off, please complete the following steps:
Step 1: Press SETUP four times, the system announces, Announcement only. Record no messages. To change the setting, press CHANGE.
Step 2: Press CHANGE until you hear the desired option (ON or OFF).
Step 3: Press TIME/SET to confirm your selection.
Step 4: Press PLAY/STOP to save and exit.
For more information on configuring Announce Only and other features of the answering system, please refer to the Answering System Operation section of the user manual.
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Despite your VoIP box shows full signal strength, there could still be no dial tone/ display Line in Use/ etc. This may due to the abnormality of signal and voltage levels. Follow this short video to reset your VoIP box and its connected devices.
(For non-IS8151 series - all other models) https://www.youtube.com/watch?v=mXbXl4froUc&t=25s
(For IS8151-X series) https://www.youtube.com/watch?v=rJ9PNkwBzfE&t=3s
[Background]
• VoIP box connected via SIM/ LAN connection.
• Some VoIP boxes have displays and some not. While displays show steady ON and ready, you might still experience with no dial tone sound/ display Line in Use.[To Reset]
• Some Power off button does not fully power off the unit. It only put the VoIP box in standby mode. To truly power off, unplug the power adapter of your VoIP box.
• Disconnect all devices from the box. After a moment, reconnect your power adapter, and then press power button to turn ON.
• Wait until the VoIP box is steady ON and ready.
• Connect your telephone cable from your Telephone base to your VoIP box.REMINDER!!!
• Make sure you didn't connect the telephone cable from the Telephone wall outlet to VoIP box telephone port!!! Doing so will not damage the device, but it will affect the call function and becomes unusable. This is why you experience no dial tone, Line in Use with busy tone, etc.
• During power outage, your landline phone will not be available since it requires external electric power despite your VoIP box has a backup battery.If this situation persists, contact your VoIP / VoIP box service provider for further support.