Re. communication, to avoid confusion please remember that ALL mobile phones use satellite signalling, the difference is whether your phone is dual band / tri band / is set up for international roaming and masses of other jargon & labels etc !!!

Go here for full information; a prepaid Kenya SIM card with a GSM international cell phone is the most convenient and economical solution while you travel in Kenya. All incoming calls while in Kenya, regardless of where they originate, are FREE! Pay the local rate for local calls and use a cellular phone in Kenya like you do at home. And unlike home, your Kenya SIM card and cell phone service is prepaid so there is no need for a contract.

You can send an SMS people can call you back, SMS you back.
If you want to make international calls you will need an international SIM, again, you can get these in Nairobi.
Forget landlines, there may be one available, maybe not.