Cables and Connectors

Internal cables commonly connect from a maker to the motherboard, the power supply to a device, the motherboard to the front panel buttons or ports, and/or from a card that occupies one expansion space to the motherboard. Cables can be tricky. Inserting a cable backward right into a maker or adapter can damage the device, motherboard, or adapter. Many cables space keyed for this reason the cable inserts into the connector just one way. However, part cables or connectors are not keyed.

You are watching: What marking on a ribbon identifies pin 1

Removing a cable for the very first time calls for some muscle. Countless cables have a traction tab or plastic piece provided to eliminate the cable indigenous the connector and/or device. Use this if feasible and carry out not yank top top the cable. Part cables have connectors with locking tabs. Relax the locking tab before disconnecting the cable; otherwise, damages can be done to the cable and/or connector.

Be careful with hard drive cables. Few of the narrow drive cables, such as the one presented in number 4.3, room not together sturdy and do not attach as firmly as some of the other computer system cables. Also, with this specific cable type, the does not issue which cable end attaches come the device. A 90°-angled cable (see figure 4.4) may attach to gadgets in a case that has actually a limited-space design and may have actually a release latch.


Figure 4.3. Both cable ends room the same


Figure 4.4. 90°-angled cable v a latch

Each cable has actually a certain number of pins, and also all cables have actually a pin 1. Pen 1 top top a cable associate to pin 1 on a connector. In the occasion that the pin 1 is not easily identified, both end of the cable must be labeled with either a 1 or 2 on one next or a higher number, such as 24, 25, 49, 50, and also so on, ~ above the other end. Pins 1 and also 2 are always on the same end of a cable. If you find a greater number, pen 1 is on opposing end. Also, the cable connector usually has an arrowhead etched into its molding showing the pin 1 connection. Figure 4.5 reflects pin 1 ~ above a ribbon cable.


Figure 4.5. Pin 1 top top a ribbon cable

technology Tip: pen 1 is the cable edge that is colored

Pin 1 ~ above a ribbon cable is easily figured out by the colored stripe the runs under the edge of the cable.

Just together every cable has a pen 1, all connectors on devices, adapters, or motherboards have actually a pin 1. Pen 1 ~ above a cable inserts into pin 1 ~ above a connector. Cables are usually keyed so the they insert only one way. Part manufacturers stencil a 1 or a 2 through the connector ~ above the motherboard or adapter; however, top top a black color connector, it’s difficult to view the little number. Number on adapters are less complicated to distinguish. Once the number 2 is etched beside the adapter’s connector, connect the cable’s pen 1 come this side. Remember that pins 1 and 2 are always on the same side, whether on a connector or on a cable. Part technicians use a irreversible marker to label a cable’s function. Number 4.6 shows an instance of a stenciled marking beside one adapter’s connector. Figure 4.6 illustrates the number 2 etched onto the adapter, yet other manufacturers stencil a higher number, such as 33, 34, 39, or 40, beside the opposite end of the connector.


Figure 4.6. Pin 1 on one adapter

technology Tip: Snug connections

When connecting cables come a motherboard or interior components, ensure the each cable is linked tightly, evenly, and also securely.

Motherboard connectors room usually notched so the the cable inserts only one way; however, not all cables room notched. Some motherboards have actually pin 1 (or the opposite pin) labeled. Constantly refer come the motherboard documentation for suitable orientation the a cable right into a motherboard connector. Figure 4.7 shows the motherboard connectors supplied for the thin cables shown in figures 4.3 and also 4.4. This connectors frequently have tough drives and optical drives attached. Number 4.8 display three various other motherboard connectors that space notched.


Figure 4.7. Motherboard connectors for small cables

Some manufacturers perform not put any kind of markings on the cable connector; even so, over there is a way to determine which method to affix the cable. Remove the adapter, motherboard, or maker from the computer. Look wherein the connector solders or connects come the motherboard or adapter. Turn over the adapter. Notice the silver- blobs, known as solder joints, ~ above the ago of the motherboard or adapter. Solder joints affix electronic contents to the motherboard or adapter. The connector’s solder joints are typically round, except for the solder share for pen 1, i m sorry is square. Look for the square solder joint on the ago of the connector. If the square solder share is not obvious on the connector, look for various other connectors or solder joints that room square. All chips and also connectors mountain onto a motherboard in the exact same direction—all pin 1s are generally oriented in the very same direction. If one pen 1 is found, the various other connectors orient in the same direction. Insert the cable so pen 1 matches the square solder share of the connector. Number 4.9 mirrors a square solder joint for a connector ~ above the ago of one adapter.

technology Tip: pin 1 is on the opposite end from the greater stenciled number

If a higher number, such together 39 or 40, is stenciled next to the connector, affix pin 1 and also 2 that the cable to the opposite end of that connector.

See more: In A Scsi Chain The Highest Priority Scsi Device Is Given What Scsi Id?

Specific cables attach a motherboard to lights, ports, or buttons ~ above the former panel. These include the strength button, a reset button, USB ports, IEEE 1394 ports, a microphone port, a headphone port, speakers, fans, the difficult drive consumption light, and the strength light, to surname a few. Be really careful once removing and also reinstalling this cables. Usually, each one of these has a connector the must attach to the ideal motherboard pins. Be certain to check all ports and also buttons as soon as you have actually reconnected these cables. Refer to the motherboard documentation if your diagramming or notes are inaccurate or if you have no diagrams or notes. Number 4.10 mirrors the motherboard pins and also the connectors.