Talking on the telephone is one of the most challenging listening situations there is. You have no visual cues to go by, such as facial expressions or lip movements, the call may be from someone you do not know with an unfamiliar voice and, at times, there is a poor connection.  
New models of cochlear implants are compatible with many smartphones and assistive apps to help with communicating on the phone. Video calling helps too as you get the visual cues that help with communication, but these are not always possible or practical.
So here are some tips to help when communicating on the phone. 
Practice Phone Calls with people you know.
Practice having conversations with people you know on the phone will be easier as their voices are familiar to you. You’ll know the friend or family member who speaks really clearly-ask them for help, not the one who mumbles their way through conversations, or ones who historically lost patience in chats with you before.
Starting out, you should be the one making the phone calls. This means you can choose a quiet spot with little or no background noise at a time of day when your concentration levels are at their best. Ask your practice buddy to do the same, to choose someplace quiet for the call (and also ask them NOT to use the speakerphone, as this can impact the sound quality of the call).
Next up, choose your preferred method of connecting your phone and processor: Bluetooth, mini-mic (or other assisted listening device), telecoil.
With Bluetooth and assisted devices, you do not have to put the phone up to your CI to listen, as the call gets streamed directly to your processor. 
To head off any potential communication barriers, frustrations or embarrassment, have a couple of planned strategies to use when you may face understanding difficulties. 
It is best to let your practice buddy know that you may not get all of the conversations and you will let them know as soon as that happens. Some helpful phrases to use are:
  • “I did not understand that part, please say it again.”
  • “I’m struggling with that, I think you said…”
  • “It helps me if you speak a bit slower…
  • “I missed that, can you tell me it again in a shorter sentence please?”
If you miss things you could ask your practice buddy to spell it, for example (J for John) or briefly describe it ("My friend John who we visited last weekend" or any other clue).
During your phone call, if there are instructions, such as information about meetings, time and place, you can check back by repeating what was said and then writing it down.
Keep those first practice calls simple until your confidence builds. A suggestion is to have a list of simple yes/no questions you can ask your practice buddy. 
  • “Did you go to work today?”
  • “Did you drive?”
  • “Are you going away this weekend?”
Build on these into short, simple conversations.
It’s helpful to prepare these practice calls in advance by writing them out like a short script that you can share with your practice buddy for them to add in their responses. 
For example, you could practice planning a trip to the beach.
  • Will you drive or will I pick you up?
  • Which day do you want to go?
  • Where shall we meet?
Also, try making an appointment with your practice buddy, then progressing from simply prepared conversations to more complex open-ended ones with no prepared script or text.
Whenever you feel ready to progress from practice calls to making calls for yourself, here are some tips to help with open-ended conversations.
In advance, write down the information you need to get from the call and the questions you should ask.
Consider the likely topics and questions that may come up.
Have a pen and pad ready to take down any notes. 
Have an introduction ready to use when calling someone you do not know or you receive a call from an unknown number, to inform them you are hard of hearing and a CI user, in case you have any communication challenges on the call.
For example: “Hello, just to let you know I may misunderstand parts of the conversation as I am hard of hearing and use a cochlear implant. I may ask you to repeat something or clarify what I have heard. Thanks for your understanding.”
With the continued advancement of mobile technology and communications, many businesses, organisations and services use text-based apps to communicate with clients; book and confirm appointments and answer enquiries, making things much easier than they used to be.
In relation to work and the commonplace use now of video conferencing tools such as zoom, request video calls and an agenda ahead of time (if there is one) so you can plan ahead of time.
Most CI manufacturers offer tips, advice and assistive devices to help with phone calls, so check out their websites too for more advice.