several (female) BNC connectors (called sockets or jacks). Most of the time, but not always, the equipment that receives the signal also has a female connector. So, the normal cable used to connect them together is a male-to-male cable with a plug on each end. Figure 9-1 shows a female BNC jack connector front and center with a male-to-male cable (containing a plug on each end) behind it. Figure 9-1 Female BNC Connector and Male-to-Male Coaxial Cable Be aware that these cables are expected to maintain a quality signal only over a very short run, and you should not expect to use cables of more than a few meters. In fact, using a cable of more than 10-15 m might mean that a signal will not be detected on the far end. There are many more details in ITU-T G.703 on the electrical and other standards behind these interface types. Of course, if the interface on the PRC/PRS does not match the interface on the router or timing equipment, then you need to get an adapter to change the gender and/or connector type. If one inter- face is unbalanced coax (50/75 ohm) and the other is a balanced UTP, then you'll need a balun to convert the impedance. This device will also convert the media type, allowing a UTP RJ-48c to be plugged into one end and the BNC coaxial cables into the other. Figure 9-2 shows a typical balun that performs both roles of media convertor and impedance matcher. Model 460F G.703 Balun S/N: 1007140036 Lot: 18091 75 Ohm RX In TX Out Figure 9-2 Balun to Convert Between 120-Ohm Balanced UTP and 75-Ohm Unbalanced Coax DIN 1.0/2.3 Connectors When performing timing projects using Cisco routers, the next most common connector on a timing interface is the DIN 1.0/2.3. The connectors on the front faceplate are female jacks, SO the connect- ing cable has a male plug. Figure 9-3 shows the front panel of a Cisco ASR-900 series router on the left, a female jack in the middle, and the male plug on the right-hand side. 10MHZ 10MHZ Figure 9-3 DIN 1.0/2.3 Jacks with the Corresponding Male Plug Because many other timing devic