The StarTech SCNM9FF is an example of a null modem cable.
Null modem adapters can also be used at the end of a straight-through serial cable to cross the lines. To enable handshaking between the two devices, the Request to Send (RTS) pin of one device must be connected to the Clear to Send (CTS) pin of the other device, and the Data Set Ready (DSR) pin is connected to the Data Terminal Ready (DTR) pin of the other. For this to work, the Transmit (TxD) pin of one device needs to be connected to the Receive (RxD) pin of the other device, and vice versa.
Simple Null Modem CableĪ Null Modem or "crossover" cable is used to connect to DTE devices together. Crossover (2) DCE (2) Direct Attach Cable (DAC) (3) Stacking (15) View More > Network Accessories. Smart Serial - Smart Serial (2) Stack - Stack (13) Stackwise-480. Shop the huge selection at CablesAndKits to find what you need today. The StarTech MXT100FF is an example of a straight-through cable. We make it our business to stock all the Cisco data cables you could possibly need. 6ft Cisco Blue RJ45 to RJ45 Rollover Console Cable 72-1259-01. 3ft RJ45 to RJ45 Rollover Console Cable for Cisco Baby Blue. This DTE Male to DCE Male Smart Serial Crossover Cable will connect two WIC-2T, WIC-2A/S, HWIC-2T, and HWIC-2AS WAN Interface cards together in back-to-back fashion. The transmit and receive lines are not cross-connected in this case, hence the name. Console Cables Rollover Console Serial Cable DB9 USB. The 26-PIN Smart Serial cable is used to connect to Cisco WAN Interface Cards including HWIC-2T, WIC-2T and WIC-2A/S. Simple Straight Through CableĪ straight-through or "one to one" cable is used to connect a DTE device (PC) to a DCE device (modem or other communications device).
DTE normally refers to the serial port on a PC or terminal, while DCE refers to a modem or other type of communications device.ĭepending on the type of device on each end of the line, you either need a straight-through or a null-modem ("crossover") cable in order to communicate. The RS-232 specification defines two types of serial devices, DTE and DCE. Straight Through Serial CableĬrossover or "Null Modem" vs. Hence, the lab instructers use serial links because they match the ports available.Īlso, consider, that serial links usually require more configuration (clocking, speed, DTE/DCE type etc), and it's more advantageous for students to see the more complex configurations than the plug-and-play type ethernet interfaces tend to be. This DTE male to DCE male smart serial crossover Cable will connect two WIC-2T, wic. Each cable is an equivalence of putting a Cisco V.35 DTE & a V. This is used to connect two routers together that have smart serial ports on it for your Cisco Certification lab. Smart Serial to Smart Serial 3 foot DTE/DCE back to back serial cable for your Cisco CCNA, CCNP and CCIE certification lab. The 26-pin smart serial cable is used to connect to Cisco WAN interface cards including hwic-2t, WIC-2T and wic-2a/S. Smart Serial to Smart Serial Crossover Cable. I've noticed that most labs used for traiing are built from older or re-deployed hardware, and hence tend to be lower specification than the latest gear - and most older routers have serial ports available by default, or at least installed when theyw ere deployed because serial links were all they had. These crossover cables out with popular Cisco router models 2801, 2811, 2821, 3825, 3845, 3640, 2621, 1721 and many others. Serial *interfaces* are not necessarily so. For example, a crossover cable is used to connect a router to another router. Pins 1,2,3,6 on the left are terminated on 3,6,1,2 on the right respectively: Key Topic: A crossover cable is used to connect two devices that operate on the same layers of the OSI Model.
Serial *connections* are more expensive than ethernet. Crossover Cable: In a crossover cable, four wires are reversed or crossed. What is the secret advantage that I still can not figure out? So why do they prefer to use serial cable?
Serial connection is more expensive and slower than Etherrnet cable. It says that: "WANS are connected over serial lines and typically operate at lower speeds than LANs, and more expensive"