A C R 3 8 S m a r t C a r d R e a d e r / W r i t e r
USB Interface
The ACR38 is connected to a computer through a USB following the USB standard.
Communication Parameters
The ACR38 is connected to a computer through USB as specified in the USB Specification 2.0. The ACR38
is working in full speed mode, i.e. 12 Mbps.
USB Interface Wiring
Pin
Signal
Function
1 V
BUS
+5V power supply for the reader
2 D-
Differential signal transmits data between ACR30 and PC.
3 D+
Differential signal transmits data between ACR30 and PC.
4 GND
Reference voltage level for power supply
NOTE
-
In order for the ACR38 to function properly through USB interface, either
ACS proprietary device driver
or
ACS PC/SC
device driver
has to be installed. Please refer to the
Device Driver Installation Guide
for more detail.
Endpoints
The ACR38 uses the following endpoints to communicate with the host computer:
Control Endpoint
For setup and control purpose
Bulk OUT
For command sent from host to ACR38 (data packet size is 64 bytes)
Bulk IN
For response sent from ACR38 to host (data packet size is 64 bytes)
Interrupt IN
For card status message sent from ACR38 to host (data packet size is 8 bytes)
ACR38 Reference Manual
Version 2.2 January 2008
Page
8
of 44
