Is the built-in WiFi on the China Telecom optical modem sufficient? After testing for a month, these four types of people really don't need to buy a router

colleague Xiao Liu moved last month to install broadband. Before leaving, the installer said, "Optical modem with WiFi, no need to buy a router." He came over to ask me half-doubtfully. I can't directly answer whether this is true or false, so I told him not to spend money yet and to use his home as a testing ground: the modem alone runs for a month, and the router is stuffed in the cabinet without moving. After a month, the accounts were settled—the master's words applied to four types of people, but for the others, they were traps. This article thoroughly covers the measured figures and criteria in one go.

to clarify: today's optical modem routers have long been integrated routers

many people think that optical modems only handle photoelectric conversion, and WiFi relies on routers—this is an old story. Since 2018, the Tianyi gateways installed by Telecom, from version 2.0 to the current 4.0, are all integrated "optical modem + router" units: dial-up, DHCP address, dual-band WiFi, four gigabit LANs, and IPTV ports—one machine covers it all. Xiao Liu's Huawei HS8145V5 is the same model as ours. I previously disassembled and compared the ports and light of each model (see this article for model comparisons) .

specs should be fair: this batch of gateways is 2.4G plus 5G dual-band, with 2.4G theoretically 300 Mbps and 5G theoretical 867 Mbps. The wireless specifications are mainstream level for the WiFi 5 generation. Some models of the new Tianyi Gateway 4.0 come with WiFi 6, but everything you build depends on the warehouse—don't get your hopes up. So the "optical modem with WiFi" is not a scaled-down version of the network; it is a complete routing feature. However, this completeness requires a few discounts. Read on for real-world testing.

a month of bare driving, the real results of the fiber modem WiFi

Xiao Liu's family situation first: a one-bedroom 55 square meters, 300Mbps telecom broadband, optical modem placed on the TV cabinet in the living room (which is crucial because no weak current box was inserted), nine internet devices in the family—two phones, one TV, one laptop, tablet, smart speaker, vacuum cleaner, camera, plus a backup phone.

I used the speed app to walk around the house three times, and the differences in results at different locations were bigger than I expected:

this report card reveals two things. First, short-range optical modem WiFi is not slow at all. In the living room, 2 meters can reach 300Mbps, comparable to an external router. The claim that "optical modem WiFi is slow" doesn't hold up at close range. Second, all the attenuation is consumed by wall penetration. The modem has two built-in antennas, but the gain is a notch below the router's external antenna. If you lose half of the 5G across a brick wall, and if you have two walls, the 5G will disappear instantly. This is a physical difference that can't be saved no matter how you adjust the settings.

real failure came on day 31. Xiao Liu added another camera, gathering the tenth device. That night, the speakers started going offline every few days. Restarting the optical modem worked well all night, and the next day it was the same. The reason isn't complicated: this batch of gateways has about ten devices in the , while the Huawei device compatibility list lists lists 10 devices from the same series. I mentioned in the 830 article that "the optical modem is at the level of WiFi usability, with ten devices on board" (the dual-band setup article) . Within ten units, it operates steadily; once this line is exceeded, it selectively disconnects, targeting devices with weak signals, causing the speaker vacuum to suffer first.

can handle the work the cat can do, so there's no need to underestimate it

to be fair, Guangmao did a good job at the basics in just one month. Dial-up has never been missed; the PPPoE setup is very familiar; The DHCP sending address has never had any issues; Plug the TV into the IPTV port to watch live streams, and use an independent channel without taking up internet speed; The laptop's network cable connects directly to the gigabit port, matching speed and WiFi. During evening rush hour, three devices can watch videos simultaneously without lag—a 300MB pool, a 4K TV uses 25MB, and each phone uses 10MB. The budget is very generous. For bandwidth choices, check out this article (how many Mbps is enough) .

also has a free benefit: the Xiaoyi Butler app lets you remotely check the modem status, change WiFi passwords, kick devices, and report faults with one click. With this for parents and parents installing at home, if something goes wrong, you can lend a hand out of town (parental control is also in this app) . This part of the experience is no worse than router apps.

so, the conclusion of the 'naked road' is that the first half is: one-bedroom apartment, fewer than ten devices, an optical modem that can be placed in the living room instead of being stuck in a weak current box, and daily video calls, online classes. The optical modem is really sufficient—the technician wasn't lying to you.

five jobs you can't handle, each one enough to annoy you once

But for the other things, just the cat alone can't handle it. In the past month, Xiao Liu's family and my own comparison have gathered five items.

First, the device was maxed out without buffering. routers claim to carry 64 or 128 devices, but my AX3000T is officially listed as 128, but I've actually installed 62 devices and it still works; Ten optical modems are the ceiling; the ninth and tenth units are pushed to the limit, with no margin. If you have smart bulbs and sockets at home, the number of devices keeps rising, and the optical modem can't keep up.

second, large units are beyond saving. is common in two-bedroom apartments and above, the optical modem has a built-in antenna that can't handle a three-bedroom plus a balcony. Plus, the optical modem doesn't have Mesh networking—it's just one unit, and there's no way to fix the dead zones. How to choose a networking solution for a large apartment? I've calculated the costs of AC+AP and Mesh in an article on (this article on network selection) . A more common pitfall is that the optical modem is stuffed into a weak current box, and when the metal door closes, the signal is cut in half. The rules about router placement also apply to the of the optical modem (the placement article).

third, advanced features are either absent or deeply hidden. advanced port mapping method, there is no entry point in the useradmin account in the optical modem backend; you have to dig through two layers to get a super password and enter telecomadmin to set it up. When I remotely connected to NAS, I went through the entire (port mapping article here) ; Common router features like QoS speed limiting, dual WAN, and USB sharing are basically absent by the optical modem. For those who want to stir things up, just the cat alone can't give them a stage.

Fourth, the cooling foundation is poor. Machines sourced carriers have tightly controlled costs, passive cooling combined with all-day WiFi load, but in summer, they feel hot to the touch. Back when my own unit had WiFi, every summer there would be one or two nights of sudden troubles and a reboot would be the best solution. This is not an isolated phenomenon; it is a common temperament of this batch of hardware.

Fifth, changes are restricted everywhere. want to dismantle dual-band integration, change channels, or change DNS, most provinces' user admins are gray, and the super password barrier blocks 90% of users; And if you change ITMS too much, it might even be pushed back in the middle of the night. I've touched the rules once (the super password article) . In short: the optical modem is designed to "let users move less," which is incompatible with the usual mismatch for tinkering enthusiasts.

four types of people don't need to buy, but which groups should buy early

gather the accounts on top into a checklist and first check which column you're on:

Xiao Liu relates to it: one-bedroom apartment, nine devices, binge-watching dramas and online classes—all four blocks right, really saving on router costs. I did the math for him in reverse: if you insist on buying it, a 200-yuan router is just for show. The signal is already good, but the bandwidth isn't enough. Better to save that money for bandwidth upgrades.

decide to add a router, there are three ways to handle the optical modem

If your target is in the "Buy Early" slots, how should you arrange the optical modem after the router arrives at home? Arrange the three routes by convenience:

Router One, the most convenient: the router acts as an AP, and the optical modem continues to manage the household. the optical modem to dial and send addresses as usual, connect the router's network cable to the ONT LAN port and WAN without use, switch the background to wireless AP mode or directly turn off DHCP. No need to set up any light mode, it's done in half an hour, beginners can choose with their eyes closed. I've drawn a diagram of the wiring details (the article on connecting two routers) .

Router 2, the cleanest: switch to optical modem for bridging, router dial-up. NAT one less layer, port mapping, public IP, and game latency all benefit, but the trade-off is getting past the super password test, having to copy the IPTV VLAN correctly, and also preventing ITMS being pushed back in the middle of the night. It's suitable for those willing to tinker (switching to full bridging) .

Route 3, do both: turn off the optical modem and WiFi. whether it's walking or road two, I recommend turning off the WiFi set on the optical modem—if you don't, your phone will always stick to ChinaNet, which has a one-bar signal, and the speed will be inexplicably cut in half. That night I turned it off, my speed increased tenfold (this article on how to disable it) . Keeping it is only useful for one purpose: to connect it in an emergency when the router is drafting.

finish with a clear order: first count the equipment and the type of home, then decide whether to buy or not; If you want to buy, start with Route 1; if you feel it's not enough after half a year, upgrade to Route 2; The first thing I did after buying it was to turn off the optical modem and WiFi. The broadband installer's words aren't just bluffing; it's just that it has its intended use—for those with a previous account, the all-in-one modem is the most cost-effective solution; If the number doesn't match, the 200-yuan router problem won't be fixed even if you spend another hundred hours later.