Jumpers and jumps
To whom it may concern,
there is always the possibility of misinterpretation of the term "jumper". From my point of view a jumper is a device with two or three pins and therefore must be contained in the schematic. E.g. it gives the choice to either ground an input or tie it to VCC.
The term "jumper" is clearly defined in the German language as "Steckbrücke", whereas a "jump" (as I call it) is defined as "Drahtbrücke". (to connect two car batteries you don't use a "jumper cable", but a "jump cable".
)
Jumps are made to connect two points of an interrupted trace using a piece of wire.
Even using the autorouter jumps can easily be made having most of the circuit routed on the copper side only, leaving some air wires, just because Eagle tends to surround itself. Check the routing thoroughly and I bet you'll get one or another laugh about the stupid routing. Correct routing as far as possible.
Go through the autorouting process again, this time activating the component layer for routing, leaving the solder side unchanged.
When routing is complete check if you can apply changes to straighten the traces on the component side.
Mark and label the jumps on the component side using thin lines (1/200") between two vias. Ripping up the connection between two vias will probably result in erased vias.
Planning for your selfmade board just don't print the component side and use the traces on the component side as a reference when placing parts (not to forget any jump).
Sending the PCB layout to a PCB manufacturer you must insist on a single layer board and ignore the component side traces.
To make sure you won't get an expensive double layered board you might rip the traces on the component side and replace the "lost" vias manually. Name both sides of the (interrupted) net equally and there will be a (hopefully straight) air wire between those vias after using rats nest.
This board layout might be turned in for manufacturing wihtout resulting in a double layer PCB.
There is always enough space to keep the jumps straight.
See attachment.
Regards
Hans