How to tell the model of a Mercury router? D191G and D191 differ by one letter, but the network port speed differs tenfold

neighbor Xiao Zheng was installing a router for her rental apartment. She sent me the product link for verification: on the same page, there were two Mercury MAC1200R, one in front and one behind, twenty yuan apart. She asked if I could buy the cheaper one, and I said not to rush to place an order—one of these two machines has a hundred-megabit port, the other a gigabit port, but the models are not a single word different.

the router model code, the manufacturer uses it as the product number, but we need to check it as the purchase password. This article breaks down the Mercury model segment by segment to clarify it, and also talks about Tenda's rules. Understanding it before placing an order helps you avoid the most expensive pitfall: only to find your broadband is choked by the network port after buying the device.

first split the D191G into four segments, each with its own message

Mercury's most classic naming format is "letter prefix + two or three digits + optional suffix." Split into four segments with the D191G, each one meaning the same:

cousin's D191G main router has been used for five years and is still in use. It's the same one from the article about changing the LAN IP port. I bought it for 190 yuan back then, with three transmissions and three retracts, all gigabit ports. This foundation can easily last a few more years today. Also at the 19 speed range, the D191 without the extension is the 100M version, plugged in gigabit broadband, with a speed cap of around 94Mbps—the machine isn't broken, but the physical limit of the network port is right there.

numbers, here are two more examples: 12 corresponds to AC1200 (2.4G 300M plus 5G 867M), D121G is this setup; 30 corresponds to AX3000 (2.4G 574M plus 5G 2402M), which is WiFi6 speed mode. There's only one rule: the higher the number, the higher the wireless speed level, but it has no conversion to broadband megawatts. Let's talk about that separately.

the worst is the suffix G: just one letter apart, but the network port is ten times worse

first settle the accounts. The theoretical upper limit of 100Mbps for 100Mbps ports is just over 90Mbps; Gigabit ports can reach around 940 Mbps of gigabit broadband. The interval between them isn't 'a bit faster, a little slower'—it's a tenfold relationship. If your home broadband exceeds 100 Mbps, 100 Mbps is a death sentence, and even if the wireless signal reaches full bars, it can't be saved.

D191 is fairly generous compared to models like the D191G, D121, and D121G, but at least you can see the differences in the model numbers. What really tricks people is MAC1200R these old classics: the same model was initially sold as the 100Mbps standard version, later released as the gigabit version, and the model name didn't include a single character. The twenty yuan difference Xiao Zheng saw was both versions posted on the page at the same time. At times like this, don't guess—just flip to the parameter table and find the 'Port' line—if it says 10/100/1000Mbps adaptive, it's the gigabit version; if it only says 10/100Mbps, it's the 100Mbps version.

there's an even easier way to check: after you get it, plug in the network cable and check the negotiation: connect the computer network cable directly to the router's LAN port. In Windows Ethernet mode, check the speed column and see 1.0Gbps as gigabit port, and 100Mbps as 100Mbps. I used this trick in my when I wrote about the Xiaomi 4A's 100Mbps and gigabit versions and the backend interfaces of both versions look exactly the same. When plugging in the cable, negotiation is the most honest.

second-hand platforms, this pitfall is even deeper. The D191 and D191G are now both used and circulating. The seller's title is uniformly labeled "same model as Mercury D191G," but the photos are taken from angles without the tail label. I help people buy second-hand routers and develop a habit: before placing an order, have the seller take a photo of the complete label on the back, then check the full line of model before negotiating—the price difference between 100Mbps and gigabit used versions isn't that big, but if you buy the wrong one and return it, you have to pay for shipping.

a quick reminder: the network port on the optical modem also has exactly the same pitfall. I've seen installers plug the network cable into the IPTV port more than once, and the symptoms are also at 93MB. that article on identifying the optical modem port has a dedicated comparison chart in the .

number is the wireless speed range, don't treat it like a broadband megabyte

the phrase "Wireless 1200M" is the most frequently enlarged on e-commerce pages, but it's completely different from "broadband 1200M." AC1200 refers to the theoretical speed of 1167M for the combined 2.4G and 5G bands. If a phone can actually run 500-600Mbps on 5G, that's already good—even if it's a wall, you'll have to pay a discount. Broadband refers to the speed at which the operator brings your line into your home—300 Mbps is 300 Mbps, not a bit more.

using the numbers from the Mercury model to compare broadband, my experience is as follows:

there's another common misunderstanding: the AX3000's 2402M is the number you can only get with a 2x2 antenna at 160MHz bandwidth. If the phone connects to 80MHz by default, it's usually 1201M. This doesn't affect the fact that it's called AX3000, nor does it affect daily use. But the big numbers on the promotional page are ideal for the budget. bandwidth issues I've written about this before. Once you understand where the negotiated numbers come from, you won't be anxious.

gigabit broadband paired with 100 Mbps ports is very common. One source is the optical modem plugged into the wrong port, buying the wrong router version is another—the symptoms are all the same. How much broadband should be installed at home, and how to estimate it, wrote a dedicated before, and you can figure it out by checking the home equipment list.

the current code for sale, what is their positioning

Mercury's main models currently sold in e-commerce channels generally fall into three categories:

Phantom and Light Shuttle are the names of the design series. The X30G, X301G, and X306G all use AX3000 speed and full gigabit ports. The differences lie in the appearance and antenna layout of minor facelifts. If you stick to the "AX3000 plus full Gigabit" trim, you won't go wrong with the choice. The M series is a Mesh kit, and my childhood friend uses a pair of M6G units with a speed of 1900M, the entire networking process and the troubleshooting of sub-router red lights previously written. M-series numbers also mean speed settings; the higher the number, the stronger the order.

one thing to be cautious about: all X-series models sold are full gigabit ports, and currently there is no mixed 100Mbps version, which is actually more worry-free. But the X30G is more like the tail end of the series, not necessarily the same as the D191G's use of "G = Gigabit"—whether the pattern can continue into new products is uncertain. Always check the spec table during inspection, don't memorize the letters.

Additionally, under the same model, there are hardware versions: V1, V2, V3, etc. You have to be sure to download firmware and find tutorials. Where to find model and hardware version there's a dedicated article. I've also covered the issue of firmware versus hardware versions on the Mercury official website in the on firmware upgrades in .

casually mentioning Tengda: its problem isn't in the internet port, but in the Pro

sort8 this stall sells Mercury Tengda all year round, and Tengda's rules are clearly explained. Tenda's prefix is: AC for WiFi 5, AX for WiFi 6, BE for WiFi 7. The numbers after this also indicate the speed range—AX3 is AX1800 (574 plus 1201M), AX12 is AX3000 (574 plus 2402M, also supports 160MHz bandwidth), AX3006 is the channel iteration of AX3000. The good news is that Tenda's models are all gigabit Ethernet ports, unlike Mercury where 100Mbps and gigabit versions are mixed together.

Tengda's own flaw lies in the Suffix Pro. AX12 and AX12 Pro come in two configurations: the AX12 uses Intel's solution, which has average heat control; Switching to the Broadcom dual-core 1.3GHz 12nm process for the AX12 Pro has clearly improved its reputation. My colleague Kobayashi's AX12 (the one in the crossover ) works fine, but if I buy something new now, I'd just go for the Pro—the price difference isn't big, the plan is one generation apart. It's the same logic as Mercury's G: the suffix letters may seem insignificant, but behind them are all real things. How to choose between the two brands for complete devices? Mercury Tengda's five-year comparison is more detailed in that .

Wrap-up: Three-Step Inspection for Assigned Items and Receipts

here's a direct copy: for broadband under 100Mbps or rental housing, D121G or even the 100Mbps version is sufficient; For mainstream households with 200 to 500 MB, the D191G clearance price or go straight to the X30G; Gigabit broadband, lots of devices, X306G or M6G paired with Mesh. If your budget goes higher, Mercury isn't the best choice; Tengda AX12 Pro or other mid-to-high-end models are more suitable.

No matter which model you buy, check the product in three steps and don't skimp on it

• look at the model suffix: D tie without G, instantly identifying the network port; If you encounter an older model with the same name for 100Mbps gigabit, proceed to step two
• check the port line in the parameter table: 10/100/1000Mbps adaptive is the gigabit port
• network cable depends on negotiation speed: if it shows 1.0Gbps, it's done; if it shows 100Mbps, contact me for a return

Xiao Zheng finally ordered the X301G, costing over 160 yuan, with 300Mbps broadband running fully loaded in his rental apartment. It was forty yuan more expensive than the 100Mbps version she had been hesitating about, but that forty yuan was a tenfold network port limit, so no matter how you calculated it, it was worth it—reading half the model code was already better than most people who placed orders with their eyes closed.