Can the Telecom optical modem be replaced by your own? I registered a used TEWA-750G for 50 yuan, and the entire LOID process is recorded

first explain why I want to change it. The optical modem sent by the telecom office for broadband had been used for five years. One summer, it started disconnecting at noon, and it took three to five minutes to redial before returning. Later, the LOS light flashed red, a technician came to measure light degradation, and the reception was -29dBm with a red line at -27. The conclusion was that the optical module was outdated and the device was replaced. Adding 150 yuan to exchange for a device is also sourced from the carrier, but I feel it's a loss—Xianyu offers a bunch of 90% new Telecom versions of optical modems priced at 50-60 yuan, and I can pick the model as I like. So I started thinking about "switching to my own." This article records my entire registration process and the pitfalls I encountered, for those who want to follow the same path.

pour cold water on the situation: you can replace it, but three things must be confirmed first

Telecom's optical modem isn't just plugged in; it needs to be 'registered' with the carrier before it can be allowed to access the network. So before you start, confirm three things—missing any one will get you stuck halfway:

First, whether your broadband is EPON or GPON. This determines what kind of cat to buy. Simply put, most telecom regions use EPON, and the optical modem packaging or stickers will be labeled; If you really can't tell the difference, look at the logo behind the 'PON' on the original optical modem sticker, or call 10000 to ask. When the EPON cat is plugged into the GPON cable, the LOS light often flashes red, physically blocking the connection. This is the first door. My region is EPON, and the rest of the process follows EPON.

Second, whether the original light modem has bound . In some regions, telecom companies bind broadband accounts to optical modem serial numbers (especially on integrated plans), so you can't dial the number on a different machine. This is the most reliable way to call customer service: "I switched broadband to my optical modem. Is there any device binding?" Not bound, congratulations, you can leave; If there is binding, ask customer service to unbind and say, "The device is yours; you need to register a new serial number," and usually it will be processed.

Third, you know your own broadband's LOID or password . This is the certificate needed for registration, which will be discussed in the next section.

What is

LOID, and where can you find it

LOID, short for Logical ONU ID, is the 'ID number' that operators use to recognize your optical modem in the EPON system. The GPON system corresponds to password authentication or SN authentication, with the same logic, just a different name. Most telecom regions use LOID authentication, usually consisting of a string of about 16 characters plus a combination of letters.

Where can

find it? Two sources:

• installation work order/installation receipt : The order the installer issued when installing broadband, which has a LOID or "Logic Identifier" section. I found mine at home, and in the lower right corner, a string of characters printed crookedly but completely.
• call 10000 or ask the installer for : provide your broadband account and installation address, and they can find it in their system. The script is straightforward: 'If the optical modem breaks, you need to replace it and register with your LOID.' After verifying your identity, customer service will notify you or send a text message. I helped a friend walk this road, and it took ten minutes to make a phone call.

a side note, some regions use "LOID + password" dual authentication during installation, and the password is also on the ticket, so you can copy it down together. If only the LOID has no password, leave the password field blank or set the default on the registration page. Try the first version and you'll understand.

Xinguang Cat in hand, the registration process goes step by step

I bought a second-hand TEWA-750G, 50 yuan with free shipping, excellent condition. The process is as follows

first step: physical connection. Insert the fiber pigtail into the PON port of the new ONC modem. Note that there is a fine needle in the flange head, align it lightly, and don't force it; if you break the pin, the wire will be useless. Power on, wait two or three minutes. At this point, the LOS light is usually flashing red, which is normal, because it hasn't been registered yet and the carrier won't recognize it.

Step two: Backstage. Enter 192.168.1.1 in the browser (TEWA defaults to this; other models check the sticker. Some Tianyi gateways run 192.168.2.1. If you can't log in, check which gateway it is. The method is written in the where 192.168.2.1 won't open). Check the sticker on the back of the device for account and password. In the telecom version, it's common to see a useradmin plus a random password. If you're not an admin, don't try blindly.

Step 3, find the registration portal. The menu is usually under 'System' or 'Management', called 'ONU Registration', 'LOID Registration', or 'Device Registration'. Click in, fill in the copied LOID format, and fill in any passwords you need. Click 'Register' or 'Apply'.

Step 4, etc. This step can't be rushed. The optical modem will restart once or twice, the PON light flashes from red to green (shaking hands with the carrier platform), and finally the PON light stays on green and the LOS light goes off—this means registration is successful. It took me six or seven minutes in total, and my friend said it took nearly twenty minutes. Efficiency varies by platform, so don't think the lights keep flashing and think it's a failure—give it half an hour.

Step 5: Verify internet access. Successful registration doesn't mean you can access the internet directly; you also need to check if the internet connection configuration in the optical modem is automatically provided. Telecom platforms usually push down the standard broadband configuration (internet VLAN, voice, IPTV, etc.), then plug in the network port and connect to the computer to try. Once you can get online, that's it. If you can't push it down, manually create a WAN connection: mode: route or bridge as you originally used, and copy the VLAN from the machine as usual—don't rush to throw away the original machine; this is where the living dictionary begins.

can't register? These four situations are based on the situation

I got stuck the first time. After registering and submitting, the PON light flashed for ten minutes and then returned to red. After thorough investigation, here are four common ways to die:

my time, it was the second type. The copy of the work order had a worn number, so I read 0 as D, rewrote it once, and it passed immediately. So I copied the LOID and checked the easily confused characters first. 0 and D, 1 and I, B and 8 are the hardest hit areas.

Successful Registration Is Just the Beginning: Three Things Not to Miss

you can get online, don't rush to quit; there are three things to do:

First, WiFi re-set the . The WiFi name and password for the new device are the previous owner or factory default. Go in the background and change it to your home name. Conveniently, separate or combine the 2.4G and 5G names as you prefer. The WiFi settings menu for custom telecom phones is easy to find. Under "WLAN" or "Network," the basic configuration section is straightforward. For WiFi channels, using the Xiaoyi Manager app on your phone is more convenient and doesn't require accessing the web backend.

second, voice and IPTV VLANs are directly copied . If your home has a telecom landline or IPTV, you need to use the old machine to fix these two connections on the new cat, especially the VLAN. If you record the wrong number, the phone won't go through and the TV will go black. I wrote about the idea of single-line multiplexing for IPTV in the article about sharing one cable with IPTV and broadband. If you want to run a VLAN, read that first.

third, prevent ITMS from reuniting with . If your own cat is registered, the telecom ITMS might notice in a day or two that "the equipment under this broadband has been replaced." Some regions issue standard configurations to overwrite your manual changes, and quotas are their standard practice. If you want the new cat to be completely under your control, you have to log in with your super administrator account and close the connection to TR-069. How to use the telecom admin super account, the scripts and risks of calling 10,000 accounts, I wrote about it in the of the Telecom Super Password, so I won't repeat it here. To be fair: if you just go online normally, a quick ITMS launch won't break anything, so you don't have to bother with this step; Only those who need to modify bridging or port forwarding on the optical modem are worth turning off.

Who is suitable to switch, and who should avoid making a mess

This table was my own summary afterward, so I took it as a reference

final tip: I've had my TEWA-750G for over three months now, and I've never had any disconnection issues. The light degradation has dropped back to -24dBm, so the fifty yuan spent is worth it. The most time-consuming part of the entire process isn't registration itself, but confirming the format, flipping the work order, and finding the LOID beforehand. Once you're fully prepared, the registration process is actually the simplest—carriers' platforms are more lenient than you might think. They only recognize LOID, not cats. Once your ID matches the cards, the door opens.