Manufacturer:
KMTronic LTD

Model:
UD4CR

Features:
- Each relay has an LED to indicate when it is operated.
- Relay outputs can be used to turn ON/OFF lights, motors and other devices.
Specifications:
Relays have Normally Open (NO) and
Normally Closed (NC) Contacts each capable of switching max:
- 12VDC/15A
- 24VDC/15A
- 125VAC/15A
- 250VAC/10A

Supply:
9 to 24V DC 
Standby current at 12V - 80mA     
Maximum current drawn by digital circuitry at 9V - 270mA
Maximum current drawen by digital circuitry at 12V - 200mA
Maximum current drawen by digital circuitry at 24V - 100mA

Dimensions:
KMTronic_4Relay_Dimension.pdf

User Manual:
Relay Controller Model UD4CR.pdf

Default: 
IP add ress: 192.168.1.1 99
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
UDP Port: 12345

UDP Commands:

FF0000 - Status Read command

FF0100 - Relay 1 OFF command
FF0101 - Relay 1 ON command

FF0200 - Relay 2 OFF command
FF0201 - Relay 2 ON command

FF0300 - Relay 3 OFF command
FF0301 - Relay 3 ON command

FF0400 - Relay 4 OFF command
FF0401 - Relay 4 ON command

UDP Test Software example including source code (C#):

KMTronic UDP Test Software.zip
KMTronic UDP Test Software Source Code.zip

More Software examples (Windows, Linux, AIX, BSD, HP-UX, Solaris e.a.):
http://info.kmtronic.com/software-examples.html