Religious devotees around the world enjoy expressing their faith with customized religious mobile phones, which may play religious ringtones, carry scripture or provide guidance, content filtering and other services specific to each religion. These phones are customized and marketed directly to religious communities in various parts of the world.

Which of the world's greatest religions, Christianity, Islam, Hinduism, Buddhism, Sikhism and Judaism (listed in order of size), has the world's greatest mobile phone?

While researching this article, I was unable to find a single Christian, Hindu or Sikh mobile phone. I'm not saying they're not out there somewhere, just that I'm "agnostic" on the point. I just don't know.

That there is no Christian mobile phone may surprise you. In fact, Christians lead the world in mobile phone accessories and software, including mobile phone stickers and cases, ringtones and Bible-related content specific to phones. So it's easy for Christians to assemble their own faith-based mobile phones from widely available "parts." But, to the best of my knowledge, nobody is selling a pre-packaged "Christian mobile phone" designed to be marketed to Christians.

Also note that, Apple iPhone is sometimes referred to as the "Jesus phone," it's not a Christian mobile phone per se, and thus cannot be included in this little contest of mine.

That leaves us with the top three contenders: Islam, Buddhism and Judaism. So here they are, listed in reverse order: The top three religious mobile phones.

No. 3: The Jewish mobile phone

A few years ago, an ultra-Orthodox rabbi approached Abrasha Burstyn, the CEO of Mirs Communications, an Israeli subsidiary of Motorola, with a proposed mobile phone concept. The result is a phone that fulfills what the rabbi saw as a need to block objectionable content from the eyes and ears of other ultra-Orthodox Jews in Israel, which by some accounts represent about 7 per cent of the Israeli population.

The phone is inaccurately referred to in the Israeli press as the "Kosher Phone." A gadget can't actually be "Kosher," but it does come with the approval of what is, essentially, a censorship board called the Rabbinical Committee for Communications.

While most religious mobile phones start out as regular mobile phones, and are augmented with additional religious "stuff," the "Kosher phone" has less, not more. It has been stripped of functionality, and simply makes and receives calls. It can't text or access the Internet. There's no camera. And more than 10,000 phone numbers for dating services and sex hotlines have been blocked.

Here's the best part. The "Kosher phone" offers steeply discounted per-minute charges when calling another "Kosher phone." But it will cost you a whopping US$2.44 a minute for calls placed on the Sabbath. To the best of my knowledge, Mirs Communications is the only wireless carrier in the world that uses its pricing structure to punish deviation from one of the Ten Commandments.

The carrier has decided, interestingly, that there is demand for phones with a similar lack of functionality among non-Orthodox but conservative Israeli Jews and Muslims within Israel and beyond.