點解有線連接仲咁重要？Why Wired Connections Still Matter
喺 Wi-Fi 6E 同 Wi-Fi 7 嘅年代，好多人以為有線連接已經過時。但事實係：對於打機、在家工作嘅視像會議、4K/8K 串流同大檔案傳輸，有線連接仍然係最可靠嘅選擇。原因好簡單——有線連接冇 Wi-Fi 嘅干擾問題、唔受牆壁阻隔影響、延遲（latency）極低而且穩定。
In the era of Wi-Fi 6E and Wi-Fi 7, many assume wired connections are obsolete. The reality is quite different: for gaming, work-from-home video conferencing, 4K/8K streaming, and large file transfers, a wired connection remains the most reliable option. The reason is straightforward -- wired connections are immune to wireless interference, unaffected by walls, and deliver extremely low and consistent latency.
延遲 Latency：有線連接通常 <1ms，Wi-Fi 通常 5-20ms（視乎距離同干擾）。對打機玩家嚟講，呢個差距係致命嘅。Wired typically <1ms, WiFi usually 5-20ms depending on distance and interference. For gamers, this gap is decisive.
速度穩定性 Speed consistency：有線連接嘅速度基本上唔會波動；Wi-Fi 速度可能因為微波爐、鄰居嘅 Wi-Fi、藍牙裝置等因素大幅波動。Wired speed barely fluctuates; WiFi can vary wildly due to microwaves, neighbours' networks, Bluetooth devices, and more.
丟包率 Packet loss：有線連接幾乎零丟包；Wi-Fi 在擁擠環境下可能有 1-5% 丟包，直接影響視像通話質素。Wired has near-zero packet loss; WiFi in congested environments can reach 1-5%, directly affecting video call quality.
香港嘅住宅環境特別適合考慮有線連接：因為單位面積細（通常 300-700 呎），路由器到任何一個房間嘅距離通常唔超過 15 米，一條網線就可以搞定。而且香港大廈 Wi-Fi 訊號極度擁擠——你嘅路由器可能要同周圍幾十個鄰居嘅 Wi-Fi 競爭頻道，令 Wi-Fi 速度大幅下降。
Hong Kong's residential environment is particularly well-suited for wired connections: with small flat sizes (typically 300-700 sq ft), the distance from router to any room is usually under 15 metres -- easily within a single cable run. Moreover, WiFi in Hong Kong buildings is extremely congested -- your router may compete with dozens of neighbours' networks for channel space, significantly degrading WiFi performance.
Cat5e vs Cat6 vs Cat6a vs Cat7 vs Cat8 完整比較
網線嘅「Cat」代表 Category（類別），數字越大理論上規格越高。但係唔係越高越好？未必。以下係各種規格嘅詳細比較：
The "Cat" in Ethernet cables stands for Category, and a higher number generally means higher specifications. But does higher always mean better? Not necessarily. Here is a detailed comparison of each category:
Cat5e — 最實用嘅選擇 The Most Practical Choice
Cat5e（enhanced Category 5）支持最高 1Gbps 速度，頻率 100MHz，最大長度 100 米。對於絕大部分香港家庭用戶嚟講，Cat5e 已經足夠。如果你嘅寬頻計劃係 100M、500M 或 1000M，Cat5e 完全可以跑滿速度。佢係最便宜、最容易買到、最柔軟易彎嘅網線類型。
Cat5e (enhanced Category 5) supports up to 1Gbps speed at 100MHz frequency, with a maximum run of 100 metres. For the vast majority of Hong Kong home users, Cat5e is sufficient. If your broadband plan is 100M, 500M, or 1000M, Cat5e can fully saturate your connection. It is the cheapest, most widely available, and most flexible cable type.
Cat6 — 略為升級 A Slight Upgrade
Cat6 支持 1Gbps（100 米內）或 10Gbps（55 米內），頻率 250MHz。佢比 Cat5e 多咗一層内部隔離，抗干擾能力更強。價錢比 Cat5e 貴約 20-40%。如果你想要少少額外嘅未來保障，Cat6 係一個合理嘅升級選擇，但對 1Gbps 或以下嘅寬頻計劃嚟講，同 Cat5e 嘅實際表現差異微乎其微。
Cat6 supports 1Gbps (up to 100m) or 10Gbps (up to 55m) at 250MHz. It includes an internal separator (spline) that provides better crosstalk resistance than Cat5e. It costs about 20-40% more. If you want a bit of future-proofing, Cat6 is a reasonable upgrade, but for 1Gbps or lower broadband plans, the real-world difference from Cat5e is negligible.
Cat6a — 10Gbps 嘅真正選擇 The Real 10Gbps Option
Cat6a（augmented Category 6）支持 10Gbps 速度（100 米內），頻率 500MHz。呢個係第一個真正可以穩定跑 10Gbps 全程嘅類別。如果你使用 HKBN 或 HGC 嘅 2Gbps 或 10Gbps 計劃，或者你屋企有 NAS 需要高速內部網絡傳輸，Cat6a 就係你嘅最佳選擇。缺點係線身較粗硬，唔太容易佈線。
Cat6a (augmented Category 6) supports 10Gbps at the full 100-metre distance at 500MHz. This is the first category that can reliably sustain 10Gbps over the full cable run. If you are on HKBN or HGC's 2Gbps or 10Gbps plans, or if you have a NAS requiring high-speed internal transfers, Cat6a is your best choice. The downside is that the cable is thicker and stiffer, making it harder to route.
Cat7 — 爭議性嘅存在 A Controversial Standard
Cat7 支持 10Gbps，頻率 600MHz，採用全屏蔽設計。但問題在於：Cat7 從來冇被 TIA/EIA（電訊業界標準組織）正式認可為乙太網標準。佢最初嘅設計用嘅唔係 RJ45 接頭，而係 TERA 或 GG45 接頭。市面上標示「Cat7」嘅網線配 RJ45 接頭嘅，嚴格嚟講唔係真正嘅 Cat7。買呢啲線唔會壞事，但你可能只係喺畀更高嘅價錢買一條 Cat6a 等級嘅線。
Cat7 supports 10Gbps at 600MHz with full shielding. However, Cat7 was never officially recognised by TIA/EIA (the telecommunications industry standards body) as an Ethernet standard. Its original design used TERA or GG45 connectors, not RJ45. Cables marketed as "Cat7" with RJ45 connectors are not strictly genuine Cat7. Buying them will not cause problems, but you may simply be paying a premium for what is essentially a Cat6a-grade cable.
Cat8 — 數據中心級別 Data Centre Grade
Cat8 支持高達 25Gbps 或 40Gbps，頻率 2000MHz，但最大長度只有 30 米。佢係為數據中心短距離高速連接而設計嘅，唔係為家庭使用。家庭環境冇任何設備可以用到 25Gbps 或 40Gbps，而且你嘅路由器同電腦嘅網絡接口通常只支持 1Gbps 或最多 2.5Gbps。買 Cat8 嚟用喺家居環境，完全係浪費錢。
Cat8 supports up to 25Gbps or 40Gbps at 2000MHz, but with a maximum length of only 30 metres. It is designed for short-distance, high-speed links within data centres, not homes. No home equipment can utilise 25 or 40Gbps, and your router and computer typically have 1Gbps or at most 2.5Gbps network interfaces. Buying Cat8 for home use is a complete waste of money.
好多人喺網上見到 Cat8 嘅廣告就覺得「越高越好」，結果用 $100+ 買條 Cat8 線嚟接自己 100M 嘅寬頻。實際上一條 $15 嘅 Cat5e 效果完全一樣。Many people see Cat8 advertised online and assume "higher is better", spending $100+ on a Cat8 cable for their 100M connection. In reality, a $15 Cat5e cable performs identically.
你嘅寬頻速度需要咩級別嘅線？Which Cable Do You Actually Need?
簡單嚟講，對號入座就得：
Here is a simple matching guide:
100M - 1000M 寬頻：Cat5e 已經完全足夠。如果想未來保障，買 Cat6。Cat5e is perfectly sufficient. Buy Cat6 if you want some future-proofing.
2Gbps 寬頻：Cat5e 理論上唔夠（上限 1Gbps），建議用 Cat6 或 Cat6a。Cat5e is technically insufficient (capped at 1Gbps), use Cat6 or Cat6a.
10Gbps 寬頻：必須用 Cat6a 或以上。Cat6 喺短距離（55 米以內）理論上可以，但 Cat6a 更穩妥。Must use Cat6a or above. Cat6 works in theory under 55m, but Cat6a is more reliable.
NAS 内部網絡 / 高速 LAN：如果你喺屋企用 NAS 做大量檔案傳輸，Cat6a 配 10GbE 網卡係最佳組合。For heavy NAS file transfers at home, Cat6a paired with a 10GbE network card is the ideal setup.
線纜長度限制同注意事項 | Cable Length Limitations
所有 Ethernet 線纜（Cat5e 到 Cat7）嘅最大有效長度係 100 米，呢個包括咗 patch cable 同埋牆內走線嘅總長度。超過呢個距離，訊號衰減會導致速度下降甚至斷線。對香港家庭用戶嚟講，呢個限制基本上唔會成為問題——就算係最大嘅住宅單位，從路由器到最遠嘅房間通常都唔會超過 30 米。
All Ethernet cables (Cat5e through Cat7) have a maximum effective length of 100 metres, including the total of patch cables and in-wall runs. Beyond this distance, signal attenuation causes speed drops or disconnections. For Hong Kong home users, this limit is virtually never an issue -- even in the largest residential units, the distance from router to the farthest room rarely exceeds 30 metres.
不過要留意 Cat8 嘅限制係 30 米，同埋 Cat6 喺 10Gbps 模式下嘅限制係 55 米。如果你喺屋企需要 10Gbps，而走線距離超過 55 米（極少見），就一定要用 Cat6a。
Note that Cat8 is limited to 30 metres, and Cat6 at 10Gbps mode is limited to 55 metres. If you need 10Gbps at home and the cable run exceeds 55 metres (extremely rare), Cat6a is mandatory.
扁線 vs 圓線：香港細單位點揀？Flat vs Round Cables for HK Flats
傳統嘅圓形網線性能最好，因為線芯之間嘅隔離同扭絞結構可以有效減少串擾（crosstalk）。但喺香港細小嘅居住空間入面，圓線有時候好難佈——佢較粗、較硬，唔容易沿住牆角走、經過門底或者收納喺地腳線後面。
Traditional round cables offer the best performance because the separation and twist structure between conductors effectively reduces crosstalk. But in Hong Kong's compact living spaces, round cables can be difficult to route -- they are thicker, stiffer, and harder to run along wall edges, under doors, or behind skirting boards.
扁線（Flat cables）嘅優勢在於極薄（通常只有 1.5-2mm 厚），可以輕鬆穿過門底、貼住牆壁走線、藏喺地毯下面。對於香港嘅租客嚟講特別實用，因為你可能唔被允許鑽牆或者做任何永久性改動。扁線嘅缺點係抗干擾能力稍差，但喺 10 米以內嘅短距離（香港家居嘅典型距離），實際性能差異微乎其微。
Flat cables are advantageous because they are extremely thin (usually only 1.5-2mm thick), easily routed under doors, along walls, or beneath carpets. They are especially practical for Hong Kong tenants who may not be permitted to drill walls or make permanent modifications. The downside is slightly weaker interference resistance, but for short runs under 10 metres (typical for HK homes), the real-world performance difference is negligible.
如果你需要走線穿過房門，買一條扁線 Cat6 係最佳選擇——薄到可以喺門關上嘅時候穿過門底而唔影響開關門。深水埗同網上都有唔同長度嘅扁線出售。If you need to route a cable through a doorway, a flat Cat6 cable is ideal -- thin enough to slide under a closed door without affecting the door's operation. Various lengths are available in Sham Shui Po and online.
唔鑽牆點佈線？Running Cables Without Drilling in HK Flats
香港絕大部分租客都唔被允許鑽牆，甚至自置物業嘅業主都未必想喺裝修好嘅牆上鑽窿。以下係幾種唔鑽牆就可以佈線嘅方法：
The vast majority of HK tenants are not allowed to drill walls, and even homeowners may not want to drill holes in their finished walls. Here are several methods to run cables without drilling:
1. 黏貼式線槽 Adhesive Cable Clips and Trunking
3M 同其他品牌嘅黏貼式線夾或線槽，可以將網線整齊地固定喺牆壁或天花板邊緣。走線路線通常係：沿住牆角向上走到天花板邊緣，再沿天花走到目標房間，然後向下落到桌面。呢個方法唔會損壞牆壁，搬走時撕除即可（建議用 3M Command 系列，撕除時唔留痕跡）。
Adhesive cable clips or trunking from 3M and other brands let you neatly secure cables along walls or ceiling edges. The typical route is: up along a wall corner to the ceiling edge, across the ceiling to the target room, then down to the desk. This does not damage walls and can be removed when you move out (3M Command strips are recommended as they leave no residue when removed).
2. 門底扁線 Under-Door Flat Cables
如上面提到，扁線可以直接從門底穿過，係最簡單嘅跨房間佈線方法。大部分香港單位嘅房門底部都有幾毫米嘅空隙，足以讓扁線通過。如果門底空隙特別窄，可以考慮將一小段扁線壓平固定喺門檻位置。
As mentioned above, flat cables can pass directly under doors, making them the simplest method for cross-room cabling. Most HK flat doors have a gap of several millimetres at the bottom, enough for a flat cable. If the gap is particularly narrow, you can fix a short section of flat cable at the threshold.
3. Powerline Adapters（電力線網絡適配器）作為替代
如果真係完全冇辦法走線，Powerline adapter 係一個替代方案。佢利用屋企嘅電力線路傳輸網絡訊號——喺路由器旁邊嘅插座插一個發射器，喺目標房間嘅插座插一個接收器，就可以透過電線傳輸網絡。現代嘅 Powerline adapter（如 TP-Link AV2000 系列）理論速度可以達到 2Gbps，實際上大約 200-500Mbps。
If running a cable is absolutely impossible, Powerline adapters offer an alternative. They transmit network signals through your home's electrical wiring -- plug a transmitter into a socket near the router, and a receiver into a socket in the target room. Modern Powerline adapters (e.g. TP-Link AV2000 series) have theoretical speeds of 2Gbps, with real-world performance typically around 200-500Mbps.
但要注意：Powerline 嘅表現極度依賴你屋企嘅電線質素同電路佈局。如果兩個插座唔係喺同一個電路上，速度可能極差。舊式唐樓嘅電線通常質素較差，效果可能唔理想。建議買之前先確認有退貨政策。
Important caveat: Powerline performance depends heavily on your home's wiring quality and circuit layout. If the two sockets are on different circuits, speeds can be terrible. Older tong lau buildings often have poor wiring, leading to disappointing results. Make sure there is a return policy before purchasing.
RJ45 接頭同屏蔽類型 | RJ45 Connectors and Shielding
所有家用 Ethernet 網線都用 RJ45 接頭。喺選購時你可能會見到以下術語：
All home Ethernet cables use RJ45 connectors. When shopping, you may encounter these terms:
UTP（Unshielded Twisted Pair，非屏蔽雙絞線）：冇額外嘅金屬屏蔽層，係最常見嘅家用網線類型。Cat5e 同 Cat6 通常都係 UTP。對家庭環境完全足夠，因為家居環境嘅電磁干擾唔算嚴重。
UTP (Unshielded Twisted Pair): No additional metallic shielding layer; the most common type for home use. Cat5e and Cat6 are usually UTP. Perfectly adequate for domestic environments where electromagnetic interference is not severe.
STP / FTP / S/FTP（各種屏蔽類型）：有金屬箔或編織屏蔽層包裹線芯，抗干擾能力更強。Cat6a 同 Cat7 通常係屏蔽線。但屏蔽線更粗、更硬、更貴，而且需要正確接地先至發揮到屏蔽效果。喺一般家居環境，UTP 完全夠用，買屏蔽線係不必要嘅開支。
STP / FTP / S/FTP (various shielded types): Metallic foil or braided shielding wraps around the conductors for stronger interference resistance. Cat6a and Cat7 are typically shielded. However, shielded cables are thicker, stiffer, more expensive, and require proper grounding to be effective. In a typical home setting, UTP is sufficient and shielded cables represent unnecessary expense.
買預製好嘅 patch cable（兩頭已經壓好 RJ45 接頭）係最方便嘅做法。自己壓接頭需要專業工具（壓線鉗）同經驗，壓得唔好會影響速度甚至連接唔到。除非你需要自定長度嘅線或者做大量佈線，否則唔建議自己壓。Buying pre-made patch cables (with RJ45 connectors already crimped) is the most convenient approach. DIY crimping requires specialised tools and experience -- a poor crimp can reduce speeds or cause connection failures. Unless you need custom lengths or are doing extensive cabling, DIY crimping is not recommended.
香港邊度買網線？Where to Buy in Hong Kong
深水埗黃金電腦商場 / 高登電腦中心 Sham Shui Po Golden Computer Arcade
深水埗係香港電腦配件嘅集散地。黃金電腦商場同高登電腦中心有多間店舖出售各種網線，Cat5e 到 Cat6a 都有齊。好處係可以即場睇到實物、比較粗幼同柔軟度，而且仲可以請店員即場幫你裁剪同壓接特定長度嘅線。價錢通常比網購平，尤其係散裝線。
Sham Shui Po is Hong Kong's hub for computer accessories. Golden Computer Arcade and Golden Computer Centre have numerous shops selling every category of Ethernet cable from Cat5e to Cat6a. The advantage is seeing the product in person, comparing thickness and flexibility, and having the shop cut and crimp a custom-length cable on the spot. Prices are usually lower than online, especially for bulk cable.
網上購買 Online Shopping
HKTVmall、Amazon、淘寶同京東都有大量網線出售。網購嘅好處係選擇多、可以睇評價、仲有退貨保障。但要注意淘寶上有唔少標示虛假規格嘅產品——例如聲稱係 Cat7 但實際只有 Cat5e 質素。建議揀有品牌嘅產品（如 Vention、UGREEN 綠聯、山澤 Samzhe），或者認準有 Fluke 測試報告嘅線。
HKTVmall, Amazon, Taobao, and JD.com all carry extensive Ethernet cable selections. Online shopping offers wider choice, user reviews, and return policies. However, beware of falsely specified products on Taobao -- cables claiming Cat7 that are actually Cat5e quality. Stick to branded products (Vention, UGREEN, Samzhe) or look for cables with Fluke test reports.
價錢參考 | Price Ranges
以下係香港市場上各類別網線嘅大約零售價（以 3 米預製 patch cable 為基準）：
Here are approximate retail prices in the Hong Kong market (based on 3-metre pre-made patch cables):
Cat5e 圓線：$10-25（深水埗 Sham Shui Po）/ $15-35（網購 online）
Cat6 圓線：$20-40 / $25-50
Cat6 扁線 flat：$25-50 / $30-60
Cat6a 圓線：$40-80 / $50-100
Cat7（配 RJ45）：$50-100 / $60-120
Cat8：$80-150 / $100-200（唔建議家用 not recommended for home use）
散裝線（未壓接頭，按米計算）更加便宜：Cat5e 大約 $2-3/米，Cat6 大約 $3-5/米，Cat6a 大約 $6-10/米。如果你需要較長嘅走線，散裝線加上壓接服務（深水埗通常 $10-20）會比買長嘅預製線平好多。
Bulk cable (un-terminated, priced per metre) is even cheaper: Cat5e around $2-3/m, Cat6 around $3-5/m, Cat6a around $6-10/m. For longer runs, bulk cable plus a crimping service (typically $10-20 in Sham Shui Po) is much cheaper than buying a long pre-made cable.
選購總結 | Buying Summary
對大部分香港家庭用戶嚟講，正確嘅選擇好簡單：
For most Hong Kong home users, the right choice is straightforward:
1. 1Gbps 或以下計劃：Cat5e 或 Cat6 扁線，最經濟實惠。Cat5e or Cat6 flat cable -- most economical.
2. 需要穿過門底佈線：Cat6 扁線係唯一選擇。Cat6 flat cable is the only sensible option.
3. 2Gbps 或 10Gbps 計劃：Cat6a 圓線，確保發揮全速。Cat6a round cable to ensure full speed.
4. 唔好買 Cat7 或 Cat8：Cat7 標準有爭議，Cat8 係數據中心用途。兩者都係浪費錢。Do not buy Cat7 or Cat8 -- Cat7's standard is disputed and Cat8 is for data centres. Both are a waste of money.
5. 買有品牌嘅產品：避免無牌雜線，認準 Vention、UGREEN、山澤等可靠品牌。Buy branded products -- avoid no-name cables, stick to Vention, UGREEN, Samzhe, and similar reliable brands.
最後提醒：一條好嘅網線可以用好多年，唔使經常更換。投資 $20-50 買一條啱規格嘅線，就可以長期享受穩定高速嘅有線連接。唔好因為慳幾蚊而買唔啱規格嘅線，更加唔好因為貪規格高而浪費錢喺唔需要嘅 Cat8 上面。
A final reminder: a good Ethernet cable lasts many years and rarely needs replacing. Investing $20-50 in the right cable delivers years of stable, high-speed wired connectivity. Do not skimp by buying the wrong spec, and do not waste money on Cat8 cables you will never need.