Why not use Mobile Phones?
Mobile phones are great for one-to-one conversations over any distance where the slow call setup time is not a hindrance to safety or efficient communications. However:
- Mobile phones have no Quality of Service (QOS) guarantees. For example the network may be down, your text message may be delayed etc. Factors outside your control. With your own (private) and well engineered radio or full duplex system you have full control of the QOS.
Mobile phones are normally One-to-One (unlike two-way radio which is usually One-to-Many)
Mobile phones are dial-up. (It takes a few seconds to select the target phone number and for the call to connect.)