Voice data wireless modem for a return of the home phone

TP-Link TL-MR6500v, 
N300 4G LTE Telephony Wi-Fi Router

My home wireless internet service has been working very reliably. However, after being rushed to hospital in an ambulance recently, I thought it might be useful to have a home phone. In an emergency I don't want to hunt around to find a phone and hope it works. So I connected my home wired phone to a 4G modem. I could not find a single Sim which would do this, so had to run two modems: one for data and one for voice.

Wireless desk phone  

My first option was to buy a 4G wireless desk phone. These look like an old fashioned analog phone, but have a slot for a SIM card and the electronics of a dumb mobile phone inside. These also act as a WiFi hub for home Internet access. They are sold in Australia for seniors, who want the comfort of an old fashioned home phone.

I found one online which also has an ethernet socket. Unfortunately when it arrived this did not work on the Telstra network. So I sent it back and tried again. I ordered another model, but the supplier had discontinued it and returned my money.

Wireless Modem with Phone Socket

For my third attempt I purchased a TP-Link TL-MR6500v, which is a slightly more expensive version of the wireless modem I already had. It is about one centimeter wider, and has a RJ-11 phone socket added on the back. The configuration settings allow the socket to be used for Voice over Internet Protocol (VOIP) or Voice Over LTE  (VoLTE). VOIP requires purchasing an additional phone service, so calls can be made. However, VoLTE uses the mobile phone account associated with the SIM card inserted in the modem. The phone is then essentially free, with the internet access.

Felix Mobile SIM

My existing Telstra data only SIM worked fine in the new router. This might have been sufficient, if I could make emergency phone calls. However, I was unable to determine, with any certainty, if I could. I tried asking Google, but got conflicting answers.

When I did this search: "Emergency call on telstra data sim", Google AI said yes, I could:

"Yes, you can make emergency calls (000 or 112) on a Telstra data SIM, even if it's a data-only SIM and doesn't have a phone number"

However when I searched on "use telstra data only sim for emergency call", Google AI said no, I couldn't:

"No, a Telstra data-only SIM cannot be used to make emergency calls (like calling 000 in Australia). Emergency calls require a voice service, which is not included in data-only SIM plans." 

I solved the problem by replacing the data only SIM with an ordinary voice/data SIM from another provider (Felix Mobile, owned by TPG). This is $5 a month cheaper than the Telstra data only service and like it is shaped to 1.5 Mbps when the data is used up (rather than being cut off).

I plugged the wireless modem into a phone socket on the wall with an RJ-11 cable (cost $1 at a second hand store). The wall phone in the kitchen, which has been unused for more than a decade, then worked (I kept the phone because it covered a large hole a lazy phone installer left). Felix Mobile uses the Vodafone network, which is different to the service I use for my phone, so if one fails, the other might keep working. The phone is powered from the wireless modem, which in turn is powered from an uninterruptible power supply, so it will keep working in a blackout.   

Amaysim

The Felix Mobile SIM worked fine for calls and data on my laptop. But it did not work at all for my set top box. I am not using the set top box for video streaming, just downloading the program guide. Even so, it appears Felix don't allow more than one data device connected at a time, the service being intended for a smartphone. I could not find a reasonably priced service with shaped data which also had phone access. So I signed up for a year long Pay As You Go (PAYG) service from Amaysim, which uses the Optus network. This charges by the minute for calls and per megabyte for data. The charges are high, but I will not be calling out from the phone normally and I have switched off data access, using the modem just as an interface to the analog phone. I have replaced the Telstra Sim for data in my old modem. I paused the Felix service, so I still have an account if needed, but am not charged (it is sitting in my dual Sim phone). This is not an elegant solution, but workable.