They allowed for the employment of thieves, who required advanced communications uplinks to transfer funds, as well as housed blueprints for Cruisers, mobile gap generators and their stationary versions and the Allied superweapon, the Chronosphere. Additionally, upon completion launch preparations would begin for a GPS Satellite, which would allow a total overview of the battlefield and overrode radar feed. However, if the satellite control in the Technology Center was destroyed, the uplink would be lost. It was advanced into the battle lab during the first and second iterations of the Third World War.
In addition to allowing the construction of high-tech units like the Cruiser and Gap Generator, building a Tech Center also starts construction of the GPS Satellite. When finished, the satellite will automatically launch. - Red Alert manual(src)
The Allied Technology Center had additional functionality compared to its Soviet counterpart in that it manufactured and launched a GPS satellite on site after completion. It also provided parts for: