CapTel 840i Frequently Asked Questions

CapTel Telephones

How does CapTel 840i work?

Captioned telephone service, provided by CapTel®, allows a person with hearing loss to make or receive phone calls with word-for-word captions of everything said to the CapTel user.

Simply pick up the phone and dial the number of the person you wish to call. The call is transparently connected to a service that provides the captions. 

At the Captioning Service, a specially-trained operator uses voice-recognition technology to transcribe word-for-word whatever is said by the other party. The captions appear on the CapTel display screen. You can hear the other party, plus read the captions to be certain of what is said. 

NOTE: The CapTel phone does not generate captions of the phone call on its own. The phone works with the Sprint captioning service (through your internet service) to display captions during your calls.

What do I need in order to use the CapTel 840i?

You will need 5 things in place to use your CapTel 840i telephone.

1. The CapTel 840i telephone

2. High-speed Internet access* 

  • Broadband or digital internet service, not dialup
    * If you do not have access to high speed internet access, please consider the CapTel 800.

3. Landline Telephone Service 

  • A standard telephone line or DSL phone service. *

  • DSL is supported if you put the appropriate DSL filter in place per your DSL provider’s instructions

  • Voice-Over IP services (VOIP) such as  cable telephone service or FIOS.

  • Not compatible with digital PBX systems found in offices or some residential facilities (unless an analog port is available).**

4. An available Ethernet port

The CapTel service must connect with a standard Ethernet cord or use WiFi access. Depending on your Internet setup, a router may be required to connect more than one device to your Internet service.

5. An Electrical Outlet 

Sprint CapTel 840i Back

NOTE: All the connection outlets (telephone, Internet, and power) should be located close to each other in the room where you want to use the CapTel 800i. If outlets are located in separate rooms, a network power adapter is available (at an extra cost) to help connect the CapTel 800i. 

What is the difference between the CapTel 800 and the CapTel 840i?

Very little.  CapTel 840i is an option if you have access to high-speed internet.   

There are two main differences:

  • CapTel 840i is for people with hearing loss who have  high-speed Internet access.CapTel 800 is for people  with hearing loss who do not have high-speed Internet access. 
  • With the CapTel 840i, anytime someone calls your phone number directly, you get captions.  With the CapTel 800, your callers may need to dial the Captioning Service phone number  first and enter your phone number in order for you to get captions*. 

Apart from the differences listed above, the two phones are nearly identical. They look the same and have most of the same features. The features and speed of captions on both phones are similar, so it is simply an option depending on whether you have access to high-speed internet or to an analog phone line.

* If you use CapTel 800 in 2-Line mode (optional), people can call your number directly, they do not have to dial the service first.

What is the difference between CapTel 800 in 2-Line mode and CapTel 840i?

Both have all the same features and benefits, they are just set up differently. 

2-Line CapTel requires two different analog telephone lines to be connected to the CapTel 800. (Applicable charges for an additional telephone line from your telephone service provider). CapTel 800i only needs one phone line and an Internet connection, which is becoming more common. There may be cost savings on your phone bill if you have purchased Internet and telephone services combined from one provider (varies by provider). You do not need to have Sprint as your telephone or internet provider.

What type of telephone line / service works with CapTel 840i?

The CapTel 840i requires telephone service to work. 

The telephone service can be: 

  • Standard analog service DSL (Digital Subscriber Line) 
  • Digital Cable phone service 
  • VoIP (Voice Over Internet Protocol) service 
  • FIOS (Fiber Optic Service) phone service 

The CapTel 840i does NOT work with digital PBX (Private Branch Exchange) phone systems found in some business settings, residential facilities, hospitals, and hotels unless an analog port is available in the PBX network.

Is an in-line filter needed when I connect the CapTel 840i to a DSL line?

For the best sound quality, all telephones including CapTel 840i should be plugged into a DSL filter in your home. Your DSL provider should give you enough filters for all your telephones. While an in-line filter is not technically required for the CapTel 840i, it will improve the sound quality of your telephone calls overall

Does CapTel 840i work with Vonage?

CapTel 840i was designed to work with Internet phone services such as Vonage, digital cable phone service, FIOS, etc. 

These services provide a telephone RJ11 jack, which you connect the CapTel 840i to using a telephone wire. As long as the telephone interface connection provides an RJ11 jack, it will work.

Do I still need my telephone service?


Yes. The Internet connection for CapTel 840i is NOT an Internet-based phone service. It only provides captions. Users must still have their own telephone service as well as an Internet connection to use the CapTel 840i. The telephone service can be any type, including analog, VOIP, DSL, FOIS, or cable phone service.

What's considered "High Speed" Internet?

High Speed Internet refers to any kind of Internet connection that is not a standard dial-up connection. 

How does CapTel 840i hook up?


The CapTel 840i plugs into a standard electrical outlet, a telephone line, and to your Internet service via an Ethernet cable. All are plugged into the CapTel 800i at the back of the phone.

Sprint CapTel 840i Back

What if my Internet connection is located in a different room than the CapTel 840i?

There are a few options that may work in your setting including: 

  • Utilize the WiFi setup on the CapTel 840i.  Simply plug in your phone line and phone's power source, when the menu asks to use WiFi, select YES and follow the steps on the screen for set up. If you do not have WiFi service, a Powerline Network Adapter kit (sold separately) lets you plug the Ethernet cable into an electrical power outlet in one room, then connect to the Internet access point in another room. Powerline Network Adapter kits are available from WCI or from a local computer electronics store. Costs may vary. 

  • Extra-long Ethernet cable 

What if I don't have an extra Ethernet jack available to plug the CapTel 840i into my Internet connection?

Utilize the WiFi setup on the CapTel 840i.  Simply plug in your phone line and phone's power source, when the menu asks to use WiFi, select YES and follow the steps on the screen for set up. If all the available Ethernet jacks in your DSL or digital cable modem are already being used, then you will need to use a Router. If all the available Ethernet jacks in your DSL or digital cable modem are already being used (by a computer, for example), then you will need to use a Router (sold separately). A Router allows you to connect more than one device to your Internet service (for example, connecting both your computer and your CapTel 840i to the Internet at the same time). A Router plugs directly into the Internet service DSL or digital cable modem. Then you plug the CapTel 840i into the Router, along with any other devices that require Internet access.

Does CapTel 840i connect to a computer?

No, the CapTel 840i does not connect to a computer. The CapTel 840i needs to connect to a modem or a Router that is connected to your internet service. It also connects to your telephone service and an electrical outlet. 

Do I need to have Sprint as my internet or my telephone provider?

You do not need to have Sprint as your telephone or internet provider.

Can I change the size and color of the captions?

Yes you can adjust both the size and the color of the captions of your calls, however changes will not be applied to the menu options. You need to set the conversation font size & colors before or after a call. You cannot make these changes during a telephone conversation.

Changing the caption font size:

You can adjust the font size the conversation captions to be larger or smaller, making the captions easier to read. You need to change the font size before or after a call; you cannot change the font size during a live captioned call.

  • With the handset hung up, press the YES button to see Options. 
  • Press the DOWN button repeatedly until Display Settings is highlighted. Press the YES button to select. 
  • Press the DOWN button until Set Conversation Font Size is highlighted. Press the YES button to select. 
  • The display screen shows what the current font size setting is. 
  • Press UP or DOWN buttons to select the font size you want: SMALL, MEDIUM, or LARGE. 
  • Once you've selected the font size, press the YES button to accept or press the NO button to exit. 
  • Press the NO button repeatedly to exit out of the menu system. 

Changing the color of the captions/background:

You can change the color of the caption font and the background color on the display screen to a color combination that you prefer.  Color choices include: WHITE, RED, GREEN, BLUE, CYAN, MAGENTA, GRAY, ORANGE, BLACK OR YELLOW.

To change the caption font and background color:

  • With the handset hung up, press the YES button to see Options. 
  • Press the DOWN button repeatedly until Display Settings is highlighted. Press the YES button to select. 
  • Make sure that Set Conversation Colors is highlighted. Press the YES button to select. 
  • The display screen shows what the current text color and background color are set to, with an pointing toward the Text Color setting. Press the YES button to select Text Color. 
  • A color palette appears on the bottom of the display. Use the UP and DOWN arrow keys to move through the various font color choices. When you find a font color you prefer, press the YES button to accept. 
  • The display moves down to indicate Background Color. Press the UP and DOWN arrow keys to move through the various background color choices. When you find a background color you prefer, press the YES button to accept. 
  • Press the NO button repeatedly to exit out of the menu system. 

NOTE: Whichever color you select for text will not be available as a background color choice.

How many lines of captions does CapTel 840i store in memory?


CapTel 840i saves up to 480 lines of captions.  As new captions are received, earlier/older captions are erased.

Does increasing the font size change the amount of captions stored in memory?

No. The CapTel 840i stores up to 480 lines of captions regardless of the font size. If you have the font size setting at LARGE, you see fewer lines at a time but the memory will still save up to 480 lines. The same is true if you select the smallest font size, although you will see more lines of captions on the screen at one time, the memory will still save up to 480 lines.

NOTE: Previously saved captions will be deleted when you change font size.

Does the CapTel 840i work like a regular phone without any Ethernet connection?


Yes, it will act like a traditional telephone.  However, if no Ethernet connection is plugged in, you will not receive captions and the display screen will show an error message. 

Can I get up to 40dB of amplification gain if I don't use captions?

No. With captions off, the maximum amplification gain is 18dB. 

How many speed dial buttons are on the CapTel 840i?

There are 3 programmable speed dial buttons. In addition, there are 97 phone book listings and 1 CapTel Customer Service speed dial button.

Will I lose any information if I unplug the CapTel 840i?


The CapTel 840i saves the phone settings, Speed Dial numbers, and Phone Book entries even when power is interrupted. However, you will lose conversation memory, time/date settings and any Caller ID information if power is interrupted.

Do I have to register my long distance carrier of choice like with the CapTel 800?

No. Because the captions portion of the call is carried over the Internet, and the phone billing is captured on your phone line like via a standard phone, you don't need to register their long distance calling plan with CapTel Customer Service. Users will be responsible for any long distance charges incurred, but the charges will appear on the user's own calling plan / regular phone bill.

Can I travel with my CapTel 840i?


Yes, however you will need to connect the CapTel 840i to an appropriate telephone line, an Internet connection, and an electrical power outlet. Connecting to the Internet in unknown locations (such as a hotel) may be challenging. You may want to consider using our Sprint WebCapTel service or Wireless CapTel by Sprint App when you travel instead.

Sprint CapTel may only be used in the United States.

I need to dial a number (dialing prefix) on my phone line to get an outside line. How do I do that with CapTel 840i?

Simply pick up the handset and dial the number needed to get an outside line. Then dial the phone number you wish to call. If you are using Speed Dial keys or using the CUST SERV speed dial button, press the number for an outside line first, then press the Speed Dial or CUST SERV button.

For Spanish captioning - do callers have to call the Spanish Captioning Service number first in order for me to get Spanish captions on the call?

No. Callers can dial your telephone number directly. However, the CapTel phone must be set to Spanish Captions Enabled in order to see captions in Spanish. You can enable this setting in the Options list.

Can I make international calls with the CapTel 840i?

No. Captioning support is only available for calls within the United States (including Alaska and Hawaii). International calls are not supported

If the power goes out, but a person has backup Internet service, would the phone lines still typically work? And if so, then does the 840i continue working?


The CapTel 840i phone requires an electrical power, phone line and Internet connection. All three must be plugged in and in working order in order for the CapTel 840i to provide captioning support. If the electrical power is out the CapTel 840i will not be able to power up and work.

Do I need to plug CapTel 840i into a surge protector? (for example during an electrical/lightning storm?)


Sprint recommends plugging your CapTel phone into a surge protector to protect it from miscellaneous electrical voltage surges and to offer some protection during a lightning storm. For maximum safety, you should unplug the CapTel 840i and refrain from using it during a lightning storm.

Why can't I view Caller ID on my screen?

You need Caller ID service from your telephone service provider in order to see Caller ID information on the CapTel 840i screen. If you do not subscribe to Caller ID service, you will not be able to view Caller ID detail.

If my Internet service goes down, will CapTel 840i still operate as a regular phone?

Yes. If you still have electrical power and the phone line is still connected you can use the CapTel 840i as a regular phone. However, you will not receive captions on your calls and the maximum amplification gain will be 18dB gain. If you do not have electrical power the phone will not work. You will see an error message on the CapTel display screen throughout your calls until Internet service is restored. 

Is CapTel 840i a VOIP service?

No. The CapTel 840i does not by itself provide Internet-based telephone service. The phone requires both telephone service and Internet service to make and receive calls. However, customers can use VOIP or Internet-based phone service with CapTel 840i - the telephone service just needs to be able to plug into the telephone jack on the back of the CapTel 840i. 

Can the CapTel 840i be hooked up to a Router?

Yes. In most cases, a Router is required to allow you to connect more than one device to your Internet service, for example connecting both your computer and your CapTel 840i to the Internet at the same time. A Router plugs directly into the Internet service DSL or digital cable modem. Then you plug the CapTel 840i into the Router, along with any other devices that require Internet access. 

Does CapTel 840i use the same Captioning Service as the CapTel 800?

Yes. The Captioning Service is the same no matter which CapTel model or method of service you use. 

Are captions faster with the CapTel 840i than with CapTel 800?


The time to initially connect to the Captioning Service is faster due to the Internet connection, but the captioning speed is the same no matter which CapTel model or method of service you use. 

Do my callers have to dial the toll free CapTel Captioning Service number first to call me like with the CapTel 800?


No. Callers dial the CapTel 840i user's phone number directly. To answer, CapTel 840i users simply pick up the handset like with any traditional telephone call. The Captioning Service will automatically connect to the call over the Internet connection.

What does "No Network Connection" prompt on my screen mean?

It means that your CapTel 840i is not receiving a signal from your internet connection, indicating it is not accessing the Internet correctly or that the WiFi service has not been interrupted. Check your connections again to confirm that everything is plugged in correctly. You can also check the ACT and LNK lights on the back (top) edge of the CapTel Phone to see if there is activity over the Internet. Check to make sure that your computer is able to access the Internet successfully.  If the light is on and you are still seeing the screen, contact CapTel customer service at 888-269-7477 or by emailing captel@captel.com.

Can I use the Internet at the same time that I am on the CapTel 840i phone with captions?

Yes. Be aware that if you are downloading very large files or streaming video on your computer at the same time you are using the CapTel 840i, you may notice some delay in the captioning speed.

Updating Your CapTel 840i Software


You can check if any new software updates are available, then update it automatically over your Internet connection. This means you’ll always be able to take advantage of the latest features & technology as long as you own your phone. 

To Update your CapTel 840i software:

  • With the handset hung up, press the YES button to see Options.
  • Press the DOWN arrow burton repeatedly until Settings is highlighted. Press the YES button to select.
  • Press the DOWN arrow button repeatedly until Update Phone is highlighted. Press the YES button to select.
  • Press the YES button to begin updating your phone, or press the NO button to exit.
  • The CapTel Phone checks to make sure that your software is up to date. If a new software version is available, your CapTel phone automatically updates to the most current version, then resets itself so you are ready to make calls.
  • Directions (User Manual)