1992 Toyota 4Runner Getting the Codes

Is there any special tools to get the codes. The book says toyota uses 2 & 7 to conect a diagnostic meter. I found a tool to get the codes and it looks like somthing that just conects to nothing. I don't have it yet but was looking at a pic of this tool. And it says to read the engin light blinking to get the codes. This is a 1992 and I haven't been able to find a code meter reader. I quit working on cars in 1986
when all you needed to do was use a wire and conect to terminels togather and the code would flash with the engin light. Hope ya can help me and I do have the codes. The truck runs but I think the cat converter is pluged.