Black Box SW723A-R4 ユーザーズマニュアル

“Serial 2-button mouse” refers to those mice that have serial RS-232 interfaces

(usually with a DB9 connector), are Microsoft compatible, and use a 3-byte, 7-bit,
1200-bps, no-parity data format. Most PC serial mice with two buttons fall into this
category.

“Serial 3-button mouse” refers to those mice which have serial RS-232 interfaces

(usually with a DB9 connector), are Mouse Systems compatible, and use a 5-byte,
8-bit, 1200-bps, no-parity data format. Most PC serial mice with 3 buttons fall into
this category.

Certain commonly available serial mice made in Asia have the usual three

buttons and a switch on the bottom. This switch is usually labeled “MS/PC”; when
it is in the “MS” position, the mouse is compatible with the “serial 2-button” setting,
and when it is in the “PC” position, the mouse is compatible with the “serial
3-button” setting.