IC693MDL754,IC693MDL754
IC693MDL754IC693MDL754
交換機(jī)在同一時(shí)刻可進(jìn)行多個(gè)端口對(duì)之間的數(shù)據(jù)傳輸。每一端口都可視為獨(dú)立的物理網(wǎng)段(注:非IP網(wǎng)段),連接在其上的網(wǎng)絡(luò)設(shè)備獨(dú)自享有全部的帶寬,無(wú)須同其他設(shè)備競(jìng)爭(zhēng)使用。當(dāng)節(jié)點(diǎn)A向節(jié)點(diǎn)D發(fā)送數(shù)據(jù)時(shí),節(jié)點(diǎn)B可同時(shí)向節(jié)點(diǎn)C發(fā)送數(shù)據(jù),而且這兩個(gè)傳輸都享有網(wǎng)絡(luò)的全部帶寬,都有著自己的虛擬連接。假使這里使用的是10Mbps的以太網(wǎng)交換機(jī),那么該交換機(jī)這時(shí)的總流通量就等于2×10Mbps=20Mbps,而使用10Mbps的共享式HUB時(shí),一個(gè)HUB的總流通量也不會(huì)超出10Mbps。總之,交換機(jī)是一種基于MAC地址識(shí)別,能完成封裝轉(zhuǎn)發(fā)數(shù)據(jù)幀功能的網(wǎng)絡(luò)設(shè)備。交換機(jī)可以“學(xué)習(xí)”MAC地址,并把其存放在內(nèi)部地址表中,通過(guò)在數(shù)據(jù)幀的始發(fā)者和目標(biāo)接收者之間建立臨時(shí)的交換路徑,使數(shù)據(jù)幀直接由源地址到達(dá)目的地址
交換機(jī)的傳輸模式有全雙工,半雙工,全雙工/半雙工自適應(yīng)
交換機(jī)的全雙工是指交換機(jī)在發(fā)送數(shù)據(jù)的同時(shí)也能夠接收數(shù)據(jù),兩者同步進(jìn)行,這好像我們平時(shí)打電話一樣,說(shuō)話的同時(shí)也能夠聽(tīng)到對(duì)方的聲音。交換機(jī)都支持全雙工。全雙工的好處在于遲延小,速度快。
提到全雙工,就不能不提與之密切對(duì)應(yīng)的另一個(gè)概念,那就是“半雙工”,所謂半雙工就是指一個(gè)時(shí)間段內(nèi)只有一個(gè)動(dòng)作發(fā)生,舉個(gè)簡(jiǎn)單例子,一條窄窄的馬路,同時(shí)只能有一輛車(chē)通過(guò),當(dāng)有兩輛車(chē)對(duì)開(kāi),這種情況下就只能一輛先過(guò),等到頭兒后另一輛再開(kāi),這個(gè)例子就形象的說(shuō)明了半雙工的原理。早期的對(duì)講機(jī)、以及早期集線器等設(shè)備都是實(shí)行半雙工的產(chǎn)品。隨著技術(shù)的不斷進(jìn)步,半雙工會(huì)逐漸退出歷史舞臺(tái)
“交換機(jī)”是一個(gè)舶來(lái)詞,源自英文“Switch”,原意是“開(kāi)關(guān)”,中國(guó)技術(shù)界在引入這個(gè)詞匯時(shí),翻譯為“交換”。在英文中,動(dòng)詞“交換”和名詞“交換機(jī)”是同一個(gè)詞(注意這里的“交換”特指電信技術(shù)中的信號(hào)交換,與物品交換不是同一個(gè)概念)。[2]
HONEYWELL UDC3200 TEMPERATURE CONTROLLER DC3200-CE-200R-210-00000-E0-0 NEW
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I Need R3HAB Sunglasses 7 DIFFERENT COLORS Glasses Rave Gear Toys
ICON Boards - Motorola MVME 162-212
ICON Boards - Motorola MVME 162-212
ICON Boards - Motorola MVME 162-212
ICON Boards - Motorola MVME 162-212
ICON Boards - Motorola MVME 162-212
ICON Boards - Motorola MVME 162-212
IFS D1010 RS232/RS422 Transceiver NEW IN BOX
IFS D1010/D1110/D1111 RS232/RS422 Transceiver TESTED
IFS D1010WDM B RS232/RS422 Transceiver
IFS D1010WDMA RS232/RS422 Transceiver New in box
IFS D1010WDMA RS-422 Fiber TRANSCEIVER 1300/850nm MM
IFS D1010WDMB R3 RS-232/422 (2-Wire) Tri-State Point-to-Point Transceivers
IFS INTERNATIONAL FIBER D1010 RS232/RS422 TRANSCEIVER
IFS International Fiber Systems D1010 / D1110 / D1111 RS232 / RS422 Transceiver
IFS INTERNATIONAL FIBER SYSTEMS D1010 RS232/RS422 TRANSCEIVER - NEW IN BOX?
IFS INTERNATIONAL FIBER SYSTEMS D1010 RS232/RS422 TRANSCEIVER WITH AC ADAPTER
IFS RS232 / RS422 D1010 D1110 D1111 Used
IFS RS232 / RS422 fiber. D1010 D1110 D1111
Includes mounting hardware
INDRAMAT 2AD 100C-B050A1-AS03-B2N1 mit Geblaese
INDRAMAT 2AD132B-B350A1BS03D2N1 USPP 2AD132BB350A1BS0
INDRAMAT 2AD132B-B350B1-BS03-A2N1 NSPP 2AD132BB350B1BS1
INDRAMAT 3 PHASE INDUCTION MOTOR 2AD100B-B050B1-AS03-A2N1
INDRAMAT 3-PHASE INDUCTION MOTOR 2AD100D-B050R5-AS03-A2N1
INDRAMAT 3-PHASE INDUCTION SERVO MOTOR 2AD100D-B050R5-AS03-A2N1 *REPAIRED*
INDRAMAT INDUCTION MOTOR 2AD180D-B350B1-BS03-A2N1
INDRAMAT MOTOR 2AD160C-B350A1-BS03-B2V2