Cable paths

Cable trays

• Cable tray 30cm above the racks: accessible only for front panel cables
• Three cable trays about 40cm, 65cm, 90cm under the floor for cables to front or back of crates
• Racks are 52U high, about 2.4m

Receivers to PPMs

• Cables run from front panel to front panel
• Shortest path: central cable tray across the front of four racks on each side (need about 5U!). Disadvantage: cant replace fan tray from upper crates. Also, maybe harder to lose excess cable length.
• Longest path: up sides of racks to upper cable tray. Disadvantage: latency.
• Middle option: always take cables up above each crate, but run cables between racks at crate height. Cable bulk at sides may still prevent removal of crates and fan trays.

PPMs to CPMs/JEMs

• Cables run from backplane to backplane
• Must use lower cable tray.

Between Merger Modules

• Front panel or backplane not decided?
• If via backplane, for four ribbon cables we could cut a small hole between adjacent CPM racks.