EMB- Firmware History

This is the firmware revision log for the EMB2 Modbus Ethernet Gateway.



September 7, 2017

This release contains the following feature additions:

A fail-safe timer was added that will detect restart the UART transmit interrupt if it failed to fire.



September 21, 2010

This release contains the following security feature additions:

Security can only be administered from the Telnet and Serial interfaces. A new menu was added that contains all of the new security features. There may be up to 3 user names and passwords configured. If no users are configured, password protection is disabled. User names and passwords are limited to 8 characters each. There is a 6 login attempt limit. After 6 failed attempts in a row, the unit will lockout all logins for a period of 10 minutes.

Each user name has an associated user ID or index. The user with ID 1 is considered the master user. It has the ability to change the other user names and passwords. The other two user ID's are limited to only changing their own user name and password. All users may modify the other system parameters.

The serial interface is not subjected to user login since it requires physical access to the unit. If the bad guys have physical access, there are much worse things they can do. This also gives a fail-safe method of clearing forgotten passwords.

From the security menu, there is also the option to disable the Web interface, Telnet interface, and SNMP agent.



May 30, 2007

IMPORTANT NOTE: You must use Upgrade Utility 3.0 or better to install this firmware in-system.

This is the initial release of the firmware for the new hardware platform.


VERSION 1.8 12/9/2005

IMPORTANT NOTE: You must use Upgrade Utility 3.0 or better to install this firmware in-system.


This release corrects some potential performance and timing problems when both serial ports are in use, one or both ports are configured for two-wire RS485, and one or both ports are in RTU mode.

- The serial driver was rewritten to reduce the occurrence of inter-character delays when transmitting a data block.

- The RS485 transmit driver control was re-implemented to insure that the the driver is disabled within 1/2 to 1 character time following the end of the data block.

- The modbus timers were modified to prevent false time-outs due to the unit being busy handling other events.



EMB2 V1.7 firmware is ready for release to production. IMPORTANT NOTE: You must use Upgrade Utility 3.0 or better to install this firmware in-system.


This release corrects the following bugs:

- This release corrects a bug in the serial port power-on self test. The bug results in a false test failure and causes the unit to go into fatal error mode blinking the "5" code. The error is caused by external serial data being received during the internal loop-back test.

- A simultaneous TCP close would cause a flood of FIN - ACK packets to be sent from the unit. Eventually it would hit a time-out and stop sending the packets. This problem seems to show up with the web server when the network has between 200ms to 400ms of latency and the web browser is Mozilla or Firefox.

- In the case that the EMB-2 initiates a TCP close, it would fail to ACK the remote's FIN packet. The remote would eventually time-out, but this would result in a few extra packets traversing the network and the remote application to briefly hang.



Apr 30, 2004


This release corrects a bug in the Firmware and adds new features.

The IP stack bug was corrected where if a user telneted to the unit through a router, it was no longer possible to access the unit from the local network.

A Gratuitous ARP will now be sent out at startup. This is being performed so that in the event a unit is being swapped out, hosts, routers, and switches will update their ARP and MAC tables.v Additional debug information was added to the port status web page. It will show the IP addresses of active Modbus/TCP connections, packet counts, and the header from the last modbus message. Seeing the modbus header can help in determining if the user has incorrectly configured the modbus addresses.

The user can now set the Ethernet Operation Mode.


Dec 17, 2002


Initial public release.

Data Comm for Business Inc.
2949 County Road 1000 E
Dewey, Il 61840
Voice: 217-897-6600
Toll Free: 800-4-DCB-NET
Toll Free: 800-432-2638
Email: Contact Page
Web: www.dcbnet.com
Fax: 217-897-8023
All DCB web pages copyright ©1995- Data Comm for Business, All rights reserved.
EtherPath®, EtherSeries®, EtherPoll®, EtherBridge® and EtherModem® are Registered Trademarks of Data Comm for Business, Inc.