If you're building a DIY rotary cellphone and are actually concerned with the practical aspects of it, probably the more important aspect is that it only suppor

If you're building a DIY rotary cellphone and are actually concerned with the practical aspects of it, probably the more important aspect is that it only supports 3G. The major US carriers have already shut down large portions of their 3G networks to free up spectrum for LTE and they will likely be completely gone in 1-2 years.