Dual SIM router? Yes that's correct. Normally mobile routers support one single SIM. Users input a SIM into the SIM card slot to dialup to mobile networks such as 3G and 4G networks.  If the routers support dual sim, users can do failover application which is a good choice for some high demanding field, such as banks, kiosk, control, live monitor, etc.

Proroute series of routers not only include single sim routers, but also dual sim models. H720, H750, H700 and H900 are the routers with two sim card slots. All models support single modem and dual modems except H900. 

Two types of backup.

A. Cold Backup

Dual sim one modem is alternate named as cold backup. There are of course two sim card slots on the Proroute dual sim 4G routers.  

How it works?

Main SIM dialups firstly, and secondary SIM keeps standby (off line). Once main SIM is offline, the router switches to secondary SIM. With this, it continue to provide the cellular connection.  

B. Hot Backup

Dual sim dual modem is alternate named as hot backup. There are also two sim card slots on the Proroute dual sim 4G routers.  One router contains two modems inside.

How it works?

Main SIM dialups, and secondary SIM also dialup. Both SIMs will be online. Normally the data traffic goes at main SIM. Once main SIM is offline, the router switches to secondary SIM immediately without waiting for dialup. With this, it continue to provide the cellular connection. 

Difference between Cold Backup and Hot Backup

The main difference is the working SIM switching time. Hot Backup gets less time around 25~55 seconds depends on network quality and modem monitor status. There are some algorithms for monitor and dialup.

Mainwhile there is another difference. Hot Backup (dual modems) can support two cellular load balancing, which makes data traffic higher efficiency.