Data Sheet

Copyright © Parallax Inc. RFID Read/Write Module, Serial & USB (#28440 / 28540) v2.1 2/27/2018 Page 2 of 10
Key Specifications

Power requirements: +5 VDC; approx. 10-20 mA idle, 100-200 mA active
 Communication: asynchronous serial 9600 bps (8N1); 5 V TTL-level, non-inverted (#28440) or
USB virtual COM port (#28540)
 Dimensions: 3.25 x 2.45 in (8.26 x 6.2 cm)
Dimensions
RFID Tag Compatibility
The RFID Read/Write Module works exclusively with the EM Microelectronics EM4x50 1kbit R/W
transponder tags. Each tag contains a unique, read-only serial number (one of 2
32
, or 4,294,967,296
possible combinations) and 116 bytes of user data area stored in a non-volatile EEPROM (Electrically
Erasable Read Only Memory). The user data area can be optionally secured with a 32-bit password to
allow only authorized read and write operations.
The RFID Read/Write Module provides, with a single command, legacy support for the EM
Microelectronics EM4100 read-only tags that are used with Parallax’s RFID Card Reader Serial (#28140)
and USB (#28340).
A variety of different tag types and styles exist with the most popular made available from Parallax.
VCC SOU T SIN GND
GRAND
idea stud io