No orders ever had to be given to establish the telegraph.
The signal service was used on the march.

The men composing this corps were assigned to specified commands.

When movements were made, they would go in advance, or on the flanks, and seize upon high points of ground giving a commanding view of the country, if cleared, or would climb tall trees on the highest points if not cleared, and would denote, by signals, the positions of different parts of our own army, and often the movements of the enemy.

They would also take off the signals of the enemy and transmit them.

It would sometimes take too long a time to make translations of intercepted dispatches for us to receive any benefit from them.