Du har rätt - det totala antalet bitar som kan vara i transit begränsas av infrastrukturen. Varje booster / slutarkombination ger ett fast antal bitar (kamerorna kan förmodligen delas mellan flera fönsterluckor och speglarna kan förmodligen delas mellan många kameror). Ju snabbare du kan göra boosters och fönsterluckor, ju fler bitar du får per kanal, men det är ändå ändamålsenligt, och om du vill få fler meddelanden kanske du måste installera ny maskinvara.
Bakgrund (med spoilers) för alla som inte har läst Time of Arrows :
In the Orthogonal universe, time and space are perfectly symmetric. There's no light-speed barrier, and no distinction between space-like and time-like intervals. Light travels in all directions in 4-space, including directions that are future-like and past-like in the local frame of reference.
As a spaceship travels faster and faster relative to an observer, its frame of reference rotates so that eventually the spaceship's direction of motion is parallel (or antiparallel) to the observer's t coordinate. That is, you can travel into a observer's future or past. (How can causality possibly work in such a universe? Read the series to find out!)
A consequence of this is that it is possible to send messages from the future into the past (in your local frame of reference, of course). The technological implementation works like this: pick a star in your distant future and point a camera at it at time t=0, with an open shutter in the camera's line of sight at a distance d from the camera. (Using mirrors to extend the light path.)
At time t=d/c (where c is the speed of the slowest-moving light that the camera can detect), close (or not) the shutter. Light from the star arrives or not at t=0, thus communicating one bit. (Note that the diagram shows the light travelling from the camera to the star: in the Orthogonal physics this is the same as the light travelling from the star to the camera.)
If you can build an automatic mechanism that can retransmit the bit in less time than t, then you can use this as a repeater to send the bit backwards from arbitrarily far in the future (so long as the system continues to run reliably for the duration):
