Nintendo 1504166 - Game Boy Advance SP Edition Console Programming Manual page 132

AGB Programming Manual
Always set a communication speed at 256KHz when performing normal
communication with the AGB Game Link cable. Communication cannot be done
properly at 2MHz.
Also, please note it will be a one-way communication due to cable connection of multi-
play communication
©1999 - 2001 Nintendo of America Inc.
132
Communication Functions
D.C.N. AGB-06-0001-002B4