I think it's a difference in tone mainly, 'come along' is a little more informal and friendly.

Saying "Come." by itself isn't really said in English conversation. If it's used at all that way, it's to sound overly formal and serious, like a butler in a haunted house ("Come. I'll show you to your room."). I never find myself saying "Come along" in conversation, although it shows up in song lyrics ("Come along, and ride on a fantastic voyage"). Most people just say "Let's go" rather than "Come along." Saying "come along" sounds old-fashioned. The more common ways to phrase it are: - Come over. "You want to come over? I got us a pizza." You only say this to mean "come over to where I'm at". - Come on. "Come on, let's go!" "Come on, you gotta tell me what she said!" - Come with me. "Come with me if you want some pizza."

I'll second Paul's answer. "Come" in the sentence would be more direct and commanding."Come along" is used here to soften the command, but in either case the meaning is the same. On a related note, "come along to Technology Support" tends to imply that the speaker will lead the person being addressed to Technology Support, whereas if the sentence read "go to Technology Support" they would be going on their own.