After 30 years I know understand why it goes 1/2, 3/6, 4/5, 7/8. Thank you!

Where do you live that has cinder block walls?

RJ45 is wider than an RJ11. RJ11 usually only has 4 connectors but can use 6. If you have an RJ11 jack and wiring you’ll be lucky to get 10Mbps max. If you have RJ45 you can still use it for telephony if you want since it will work. The bigger question would be, where does that line go and what type of cabling. Even if you’re fine with 10Mbps, if it connects to the POTS network you’ll just succeed in frying your devices if the Ring and Tip lines are shorted.

Username checks out.