Sony MVS-8000 User Manual page 27

Each button has assigned to it a video signal and a key signal, forming a pair.
You can set these video and key combinations in a Setup menu.
For details of Setup menu operations, see "Cross-Point Settings (Xpt Assign
Menu)" in Chapter 16 (Volume 2).
Cross-point button control block button numbers
On the M/E and PGM/PST banks, each cross-point button has two button
numbers, and you use the [SHIFT] button to switch between these numbers.
The button numbers are as follows.
26
Signal Selection