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If the device is configured so that it directly uses DLMS/COSEM protocol on the given interface, set this parameter to "Direct HDLC".

Mostly (e.g. when reading through IR optical interface by an optical reading head) you must open the connection in IEC protocol in so-called "mode E" and then transfer to HDLC binary protocol (i.e. DLMS/COSEM).

"IEC mode E", according to the specification of IEC protocol, uses the following settings of the transmission parameters:

• baud rate 300 Baud,
• 7 data bits,
• even parity,
• 1 stop bit.

If "Opening Mode" is set to "IEC mode E", the above-mentioned transmission parameters must be set. As for the Serial communication line, the parameters must be set in the line parameters "Mode 1". See the protocol parameter "Software 7E1".

The setting of the baud rate to 300 Baud is usually not required when using the line of the MODEM category. A so-called DTE speed is used between a PC and a modem. If this speed is higher than 300 Baud, you have to activate the "handshaking" parameter on RTS/CTS in proper line mode.

If the parameter value is set to "Direct HDLC", a dynamic change of transmission parameters is not expected. You can use any Serial line mode and set it by the "Line mode" parameter on the station.

More information is mentioned in IEC 62056-21, Electricity metering - Data exchange for meter reading, tariff and load control - Part 21: Direct local data exchange, Annex E: "METERING HDLC protocol using protocol mode E for direct local data exchange".

See also chapter "Setting of transmission parameters".

The "UDP Pure" mode is used by some devices when communicating over UDP. Each DLMS/COSEM data packet (challenge/response) is in a separate UDP packet. In the case of TCP, this is problematic (without parsing it is not possible to determine what the size of the DLMS/COSEM data packet is) so the DLMS/COSEM standard defines the use of an envelope - called a Wrapper - for TCP/UDP mode (see next paragraph).

The "TCP/UDP Wrapper" mode is used when communicating over TCP or UDP. An 8-byte header (Version, Wrapper Source Port, Wrapper Destination Port, and Length fields) is added to the DLMS/COSEM data.

The "TCP/UDP Wrapper + Gateway protocol" and "Gateway protocol" modes are used when communicating over TCP or UDP through a so-called Gateway device. A prefix is added to the DLMS/COSEM data (single-byte fields Header, Device Network ID, Address Length, and variable-length field Device Address). Based on the Device Network ID and Device Address, the Gateway can distinguish which target device to route the request to. The device response is routed to the D2000 kOM process, and the prefix this time contains its identification (My Network ID, My Address).
In addition, in the "TCP/UDP Wrapper + Gateway protocol" mode, the same header as in the "TCP/UDP Wrapper" mode is added. When using UDP, some devices may omit the header, similar to the "UDP Pure" mode.

Direct HDLC
IEC mode E
UDP Pure
TCP/UDP Wrapper
TCP/UDP Wrapper + Gateway protocol
Gateway protocol

See "DLMS UA 1000-2 Ed. 7.0" document, chapter 8.4.2.3 "Reserved special HDLC addresses".
For ADDAX NP73E.2-18-1 a different value than 10H had to be configured (1 or 2).

A Disconnect request will not be used after the readout of values from a device is finished. During the next readout, a connection establishment phase is omitted (HDLC mode-setting request and AARQ negotiation request).
This allows for greater data throughput and an increase in the frequency of reading values from the device.

Online address selection from the list of objects, directly on the device, through the DLMS Object List dialog box in the configuration of the I/O tag address will be disabled.
Disabling of browsing makes sense in a production environment if values are to be read on a several-seconds basis and reading a list of objects, which can take up to several minutes, is not acceptable.
Some devices (e.g. ADDAX NP73E.2-18-1) do not support reading of the object list.

Several electrometers implement optimization of time data when reading from profiles (class_id=7). The optimization means that only the first row of data contains a timestamp, others contain null. The timestamp of each row is equal to the previous row's timestamp plus the value of the capture_period (4) attribute.

If the value of this parameter is YES, the value of the capture_period attribute is read prior to reading the profile data. If the value of this parameter is NO, the content of the capture_period attribute is not read, but the KOM process relies on all profile rows to contain timestamps. If this is not the case, the profile data is not read, and the line logs contain error messages "turn on station parameter 'Profile Data Optimization".

Bit settings in the "xDLMS Conformance" field in the AARQ initial message. The default settings are:

• for Application Context "Short Name (SN) referencing" bits read/write bits
• for Application Context "Logical Name (LN) referencing" bits get/set/parameterized-access bits

Setting it to YES activates an SW emulation of transmission parameters of 7 data bits and even parity when the transmission parameters of 8 data bits and none parity are set (i.e. emulation of 7E1 when 8N1 is set). It enables the use of the "IEC mode E" option for SerialOverUDP lines that do not support dynamic changes of transmission parameters.

See the chapter Settings of transmission parameters.

Nonzero value activates the sending of a so-called "wake-up message" which activates the communication interface of battery-powered devices. The null characters (0x00) are sent according to the quantity that is defined by the parameter value. The baud rate must be 300 Baud (configured in "Mode 1" for Serial lines).

More information is available in IEC 62056-21, Electricity metering - Data exchange for meter reading, tariff and load control - Part 21: Direct local data exchange, Annex B: "Wake-up methods for battery-operated tariff devices".

If a so-called "wake-up" message is activated, this parameter defines a delay after sending a "wake-up" message, before the beginning of communication. In the case of a Serial line, we recommend setting the "WaitTxEMPTY" parameter in a specific line mode.

According to document IEC 62056-21, you should set this parameter between 1,5 and 1,7 seconds.

This parameter is used if the "Opening mode" protocol parameter is set to "TCP/UDP Wrapper" or "TCP/UDP Wrapper + Gateway protocol". It specifies the value of the Source Port field (2-byte number) in the wrapper header.

Reserved ports are according to the standard:

• No-station: 0x0000
• Client Management Process: 0x0001
• Public client: 0x0010
• Open for client SAP assignment: 0x02 .. 0x0F,  0x11 .. 0xFF

This parameter is used if the "Opening mode" protocol parameter is set to "TCP/UDP Wrapper" or "TCP/UDP Wrapper + Gateway protocol". It specifies the value of the Destination Port field (2-byte number) in the wrapper header.

Reserved ports are according to the standard:

• No-station: 0x0000
• Management Logical Device: 0x0001
• Reserved: 0x0002 .. 0x000F
• Open for client SAP assignment: 0x0010 .. 0x007E
• All-station (Broadcast): 0x007F

The delay after sending the request but before reading the response.

Explanation of recommended settings:

S37=5   1200bps DTE-DTE speed - limits the speed for modems. Many devices use modems with limited transmission speeds and this setting can speed-up the connection establishment process. Higher transmission speeds must be negotiated individually.

&D2   DTR drop to hangup - for matching with the parameter of modem line (line configuration, tab "Modem - parameters", check the "Use DTR for Hangup" option).

S0=0   Disable auto-answer. Auto-answer will not be used.

S30=2   20 sec inactivity timeout - automatic hangup after idle timeout expired. Necessary for assuring connection termination after the communication with the last device is over.