IEC 60870-5-104 (also known as IEC 870-5-104) is an international standard, released in 2000 by the IEC (International Electrotechnical Commission). As can be seen from the standard's full designation 'Network access for IEC 60870-5-101 using standard transport profiles', its application layer is based on IEC 60870-5-101.

IEC 60870-5-104 enables communication between control station and substation via a standard TCP/IP network. The TCP protocol is used for connection-oriented secure data transmission.

IEC 60870-5-104 limits the information types and configuration parameters defined in IEC 60870-5-101, which means that not all functions available in IEC 60870-5-101 are supported by IEC 60870-5-104. For instance IEC 60870-5-104 does not support short time stamps (3-byte format), the length of the various address elements is set to defined maximum values. But in practice, vendors very often combine the IEC 60870-5-101 application layer with the IEC 60870-5-104 transport profile, without paying attention to these restrictions. This might then lead to problems, if a device strictly applies the standard.

Interoperability between devices by different vendors is ensured by the interoperability list, which is defined by the standard. In the list, the function range is defined for each device by marking the applicable functions. The common denominator between different vendor lists defines the possible function range.

The biggest advantage of IEC 60870-5-104 is that it enables communication via a standard network, which allows simultaneous data transmission between several devices and services. Apart from this, the same pros and cons apply to IEC 60870-5-104 sand IEC 60870-5-101. Issues that remain to be dealt with are the definition of communication with redundant systems or networks and, with the use of the internet, data encryption.

ISO/OSI Model

7	Application Layer	IEC 60870-5-104 Companion Standard IEC 60870-5-5, IEC 60870-5-4
6	Presentation Layer	n/a
5	Session Layer	n/a
4	Transport Layer	TCP (RFC 793)
3	Network Layer	IP (RFC 791)
2	Link Layer	PPP (RFC 1661 & RFC 1662)	Transmission of IP datagrams over ethernet network (RFC 894)
1	Physical Layer	X.21	Ethernet (IEEE 802.3)

Supported Information Types

Control Direction	Single Command
	Double Command
	Setpoint
	Regulating step command
Monitoring Direction	Single indication [1 Bit] with quality
	Single indication [1 Bit] with quality and time tag
	Double indication [2 bit] with quality
	Double indication [2 bit] with quality and time tag
	Measured scaled value with quality
	Measured scaled value with quality and time tag
	Measured normalized value with quality
	Measured normalized value with quality and time tag
	Measured floating point value with quality
	Measured floating point value with quality and time tag
	Bitpattern [32 bit] with quality
	Bitpattern [32 bit] with quality and time tag
	Counter value with quality
	Counter value with quality and time tag
	Step position value with quality
	Step position value with quality and time tag
	Event of protection equipment with quality and time tag

Protocol Features

Application Layer	On-demand transmission (e. g. single indications, analogs, ...) Spontaneous transmission (e. g. single indications with time tag, ...) Direct command transmission (with select before operate) Clock synchronization File Transfer
Address Space	Common Address of ASDU: 1..65535 Information object address: 1..16777215

Implemented Protocol Stacks

IEC 60870-5-104, Master

IEC 60870-5-104, Slave

Applicable Products

	ipRoute	Router for IEC 870-5-101 and IEC 870-5-104 protocols *start price 970,- €* Details...
	ipConvLite	inexpensive protocol converter for standardized application *start price 1.800,- €* Details...
	ipConvOPC	Softwarepackage for conversion between OPC DA 3.0 Server and standard protocols Details...
	ipConvPS	Universal protocol converter with integrated Profibus-DP, Slave interface Details...
	ipConvPM	Universal protocol converter with integrated Profibus-DP, Master interface Details...
	ipConv	Universal protocol converter for highest degree of flexibility Details...
	Fink WinPP Protocol Simulator	Simulationsoftware for IEC 60870-5-101, IEC 60870-5-103, IEC 60870-5-104, SINAUT 8-FW 16-1024 PCM/DPDM Details...

References

Storebælt, Denmark Details...	Denmark	ipConv	IEC 60870-5-104, Master / IEC 60870-5-104, Slave / Simatic TDC, Master / Modbus TCP/IP, Master /
DEWA DCC Distribution Control Center Details...	United Arab Emirates	ipConv ipConvLite	IEC 60870-5-101, Slave / IEC 60870-5-101, Master / IEC 60870-5-104, Slave / XMAT, Master /
DEWA TCC Transmission Control Center Details...	United Arab Emirates	ipConv ipConvLite	IEC 60870-5-101, Slave / IEC 60870-5-101, Master / IEC 60870-5-104, Slave / XMAT, Master /
ELIA Details...	Belgium	ipConv	Modbus TCP/IP, Master / IEC 60870-5-104, Slave / Telegyr 065, Master / Telegyr 102, Master / Telegyr 809, Master / Tracec 32, 62, 92, 92P, 122, 130 & 142 Master /
SEC SVC, Saudi Arabia Details...	Saudi Arabia	ipConv	IEC 60870-5-101, Slave / IEC 60870-5-104, Slave / IEC 61850, Client / Simatic TDC, Master /
BLS AlpTransit - Lötschbergtunnel Details...	Switzerland	ipConv ipRoute	OPC DA 3.0 Server / IEC 60870-5-104, Slave / IEC 60870-5-101, Master / IEC 60870-5-104, Master / SNMP, Client /
Mainova Communication Hub Details...	Germany	ipConv	OPC DAXML 1.01 Server / IEC 60870-5-104, Slave / IEC 60870-5-101, Master / Modbus, Master / SEAB 1F, Master /
Manny Canjar Details...	Columbia	ipConv	IEC 60870-5-101, Slave / IEC 60870-5-104, Master / IEC 60870-5-104, Slave / Indactic 33/41, 2033, Master /
Yunnan-Guangdong, China Details...	China	ipConv	IEC 60870-5-104, Slave / Simatic TDC, Master /
FSC HECHI Details...	China	ipConv	SC1801, Slave / IEC 60870-5-104, Slave / IEC 60870-5-101, Slave / Simadyn-D, Master /