I'm current using maxis provided router TP-Link Archer c5v ac1200 and i'm planning to get a new router, probably tp-link ax series router.

But there a problem. My maxis plan have a phone line, and its connected to the c5v router that have a rj11 port. If i changed a new router without rj11 port i cant use the phone.

My modem Huawei EchoLige HG8240H5 have a rj11 port and i noticed some unfi user connect their dect phone to the modem (same model), i tried but its not working the phone (only have beeping sound, tel indicator dint light even i pick up the phone). The phone only can work by connect the router, even i unplug the rj11 cable the voip indication still solid (blinking if have incoming call or during call).

How to solve this problem if i change a new router? Is there any solution to make the phone work on modem?

Cancel the phone line. No one uses it anymore.

Alternatively, get a GSM to RJ11 box. It converts ordinary phone into GSM. I used this solution previously for my old alarm system.

Last time i was told by an installer, unifi always use the 1st RJ11 port on the modem for their phone line while maxis/etc will use the 2nd RJ11 port but it does need to be configured 1st i think..

This option may or may not work, but can give it a try if you already have the new router. First disable internet and wifi from the C5 then set to bridge mode. Connect the new router to BTU to setup as usual. Choose Maxis as the ISP profile. Then, find the vlan setting on the router, identify which lan port is configure for the Maxis voip.
Connect the router to the lan port designated for voip, and the other end of the lan cable connect to the C5 wan port. Restart everything and see if your phone line is working.
Need to trial and error for this method, as some said it work while some cannot get the phone line to work at all.

Another option is to have the C5 router connect to BTU, do vlan tagging 621 on your custom router and connect lan 4 of the C5 to wan port of the custom router.

This post has been edited by YoungMan: Sep 3 2023, 09:14 PM

You have a few options

1. You CANNOT use the RJ11 ports on the Huawei because it is for TM use only
*in some rare cases, maybe possible if you are on Maxis Own Infra, advanced setup needed

2. easiest,
Huawei -> New TP-Link -> Old TP-Link with wifi and other features disabled, just use for phone

3. next one is not recommended!
the above but flipped, old tplink first then new tplink, not good, you will encounter double NAT, but most plug and play solution

4. IP Phone with LAN Port, requires some setup, see
https://forum.lowyat.net/topic/5243640

5. just dont use the phone

6. renew contract with maxis to get new router

7. change isp