At my work they use a 8-port switch at their main control panel. The 8 Ethernet ports on the switch are connected to the computers in the office. The problem is, there is a ninth rj45 cord that needs to go into the switch too. Is there some kind of a splitter, a Y-cable, or something to be able to add the ninth wire to it? Also, is there any such thing as a 10-port switch, or does it jump to 16 ports from 8?

Jumps to 16 I picked up a new one from Amazon because I too need that 9th and 10th port but after move all my net cable to the new switch I ended up using 12 Ports. You could add a 5 Port Switch as well.
At Our Tech meeting a work this week our Telcom Tech was up dating to some new switches and said that he had to learn a few new items about and I out loud said what lean how to turn a switch on and off. I went over really well and at least we had a good laugh in our meeting.
 

If you are worrying about cost and do not need managed, then consider 1 of the many 5 port Gigabit units.  Alternate if you are doing slower a 10/100 switch is even less expensive.  You would just add your additional units to the 1,2,3 or 4th port and plug the 5th port into the existing 8 port unit. 

bcavnaugh
Jumps to 16 I picked up a new one from Amazon because I too need that 9th and 10th port but after move all my net cable to the new switch I ended up using 12 Ports. You could add a 5 Port Switch as well.
At Our Tech meeting a work this week our Telcom Tech was up dating to some new switches and said that he had to learn a few new items about and I out loud said what lean how to turn a switch on and off. I went over really well and at least we had a good laugh in our meeting.
 

When you add a 5-port switch, is there a short cord included that you plug from the 8-port to the 5-port? How does it work. Any pics you can find might help.

ty_ger07

XrayMan

ty_ger07
You can't adapt/splice ethernet cords together. If you could, you wouldn't need a switch in the first place. You need a junction with logic (switch) to handle all the machines' ip addresses and masks, route traffic to and from each specific machine, and prevent interference and two machines talking at the same time. You need a second switch or a bigger switch.

I didn't want to splice any cords. I just either want to add to the 8-port, or just get another one that has more ports. Need to see which is better at this point.

XrayManIs there some kind of a splitter, a Y-cable, or something to be able to add the ninth wire to it?

Splitting or Y-ing two cord is effectively splicing them together since you are combining the wires in pairs to a single output.

Ok, got it. I read into what you said too much.