The communication system is used to connect the floor fixtures (e.g. elevator diplays, elevator call butons) to the control panel which is existed in the elevator machine room.

Please look at the following picture:

![schematic](https://i.stack.imgur.com/g5vtm.png)

[simulate this circuit](/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fg5vtm.png) – Schematic created using [CircuitLab](https://www.circuitlab.com/)

*Dn* represents the device connected at nth floor.

The first system uses serial communication (e.g. Canbus) to connect the devices to the control panel. The second system uses multihop wireless network to exchange information between the devices and the control panel.

**Which system should I use from both a technician and a business perspective? Why?**

**Assumptions:**

1. This is a 5 floor elevator.
2. Low data rate is sufficient.

I have asked many people who are working in this field; and I got answers (may be right or wrong) with no **facts** or **prove**. Links to the questions [(1)](https://www.quora.com/What-is-a-comprehensive-answer-to-why-elevator-companies-would-prefer-using-wireless-technology-over-the-other-approaches), [(2)](https://www.quora.com/Why-do-elevator-companies-head-toward-wireless-elevators).

They claim that even though wireless system has higher initial cost, it is more cost effective.

There are many patents on the internet of famous companies that started to use wireless technology. It is mentioned in this [patent](http://www.google.ch/patents/US6446761) that the main reason for using wireless (and here where I got surprised) is to reduce the number of wires. I mean, how many wires are there in a serial communication system? (2 for Canbus). 
Why would you prefer using about 10 wireless modules (for 5 floor elevator) to avoid using a 2 wire cable.

**With that being said, would you shed light on my question?**