Link Port

• What does pin 4 of the link port do?
• Can the serial link port be used to connect to other serial devices?
• I'm trying to write code to communicate with another GB using the link port. Are there any suggested algorithms for doing this?
• I get an unreliable game link connection when connecting a GB Pocket or Classic to a GBC. What might cause this?
• Is the GB link connector available anywhere?
• With the introduction of the GB Pocket the link port connector is smaller than it was on the GB Classic. Are the changes only physical?
• Is there any direct way to read or write any of the pins on the link port?