Both. Sometimes I call her when she is literally holding the phone to dial me (I guess we have a telepathic connection), or I call her. There are times she will call to check on me if she hasn't heard from me for more than a day, or if she wants to ask me something, but we talk pretty much daily, at least during the week. I call her on my drive home from work. Sometimes she will call me at work, but very rarely, since I always call her in the evenings anyway.
She has a cellphone she always keeps off (I don't get why but have been gotten nowhere with that when trying to explain that cellphones are only useful if they are on and people can call!) so she only relies on her landline. If I cannot reach her, I leave her a message on the answering machine. Her phone lights up red when she has a voicemail, so she is pretty quick to respond.