This Standard is submitted for final approval to NMRA BOD July 2012. This document is a direct translation of the Lenz document, v1.2, dated May 2012 in German. The German language is left in the document as the primary authority.
Alle Rechte, Änderungen, Irrtümer vorbehalten. Nachdruck und jede Art der Vervieffaltigung, auch auszugsweise, gleichgültig auf weiche Art, sind verboten. Spezifikationen un Abbildungen sind ohne Gewahr. All rights reserved, subject to change without prior notice, errors and omissions excepted. Reproduction or any form of duplication, in whole or in part is prohibited regardless of type. Specifications and illustrations are made without guarantee. Lenz Elektronik GmbH, Hüttenberstraße 29, 35398 Gießen, Tel.: 06403 900 10, Fax.: 06403 900 155, info@lenz-elektronik.de

1.
Overview
Die von Lenz Elektronik entwickelten und verwendelen elektronischen Steuerungen, insbesondere jene betreffend des Europäischen Patents 1 380 326 B1 werden unter des markenmaßigen Kennzeichnung "RailCom" angeboten und in den Verkehr gebracht. "RailCom" is  eine auf den Namen von Lenz Elektronik für die Klass Sleuerungen" unter der Nummer 301 16 303 eingetragene Deutsche Marke sowie ein für die Klassen 21, 23, 26, 36 und 38 " Electronic Controls for Model Railways" in U.S.A. unte Reg.Nr. 2,746,080 eingetragenes Trademark Diese Spezifikation git ausachließich für die Anwendung von RailCom innerhalb des DCC-Datenformats (Protokolis). Die Anwendung von RailCom innerhalb ander Lenz Electronik GmbH developed the electronics controls covered by the European patent 1 380 326 B1 that is offered and marketed under the name "RailCom". "RailCom" is a German trademark registered by Lenz Electronik for Class 9 "Electronic Controls" under the number 301 16 303. "RailCom" is also a USA registered trademark for Classes 21, 23, 26, 36, and 38 "Electronics Controls for Model Railways" under Registration No. 2.746.080. This specification is valid exclusively for use of RailCom when used with the NMRA DCC data format (protocols). The use of RailCom with other data formats is not permitted. As a prerequisite for this Standard, a Digital Command Station transmits information to Digital Decoders by sending a series of bits using the NMRA digital signal described in S-9.1. This sequence of bits, termed a packet, is used to encode one or more instructions that the Digital Decoder operates upon as described in S-9.2, S-9.2.1, and S-9.2.2. This Standard specifies how a Digital Decoder transmits in response to this received NMRA packet by generating a series of pulses during a specified absence of track power. This series of pulses is received by an external device called a detector. To successfully accomplish this transmission, and conform to this Standard, the Digital Decoder must satisfy both the Electrical Specifications (Physical Layer) and the General Feedback Packet Format specifications specified contained in this document. Portions of intellectual property needed to develop products that utilize this Standard have been licensed to the NMRA by Lenz GmbH under patents 6,494,410 and 6,853,312 and by Stan Ames under patent US 6,539,292 B1. The NMRA grants a no-cost sub-license to use the technology covered by this intellectual property to any user for their personal non-commercial use. The NMRA will grant a no-cost sub-license for the use of this technology for any Manufacturer's DCC product that the NMRA certifies meets all the requirements contained within this STANDARD and has been granted a C&I Warrant by the NMRA.
2.
Physical Layer
This section describes the RailCom physical layer.
2.1. General Information
Der Informationsfluss im DCC-System erfolat normalenweise von der Zentrale (Booster) über das Gleis zu den  Decodern. Für die umoekehrte Übertragungsrichtung ist es erforderfich diesen Datenstrom zu unferbrechen. Dies geschieht durch die Booster die dazu am Ende eines jeden DCC-Packets ein sogenantes RailCom-Cutout erzeugen ind sorgung trennen und kurzschließen. Die eigentliche Datenübertragung erfolgt mittels einer Stromschleife. Den dazu for und Decoder während des RailCom h Strom muss der Decoder aus seinem internen Puffer bereitstellen. Abbildung 1 zeigt die Anordnung von Booster, Del The information flow in a DCC system normally takes place from the command station to the power station (booster) to the decoders by means of the track. The reverse transmission of information from the decoder requires the interruption of power and this data stream. This interruption is occurs via the boosters that produce a so-called RailCom cutout, at the end of each DCC packet, by disconnecting the two TRACK wires from the voltage supply and shorting them. This function group inside the boosters is called a cutout device. Such a cutout device could also be executed as a separate entity outside of the booster. The actual data transfer occurs by means of a current loop. The decoder must provide the necessary current for the transfer from its internal cache. Figure 1 shows the arrangement of booster, detector, and decoder during the RailCom- cutout.
2.2. RailCom – Transmitter in the Decoder
Um eine 0' zu übertragen muss der Decoder einen Strom I von 30-44/8 mA liefem bei einem Spannungsabeal am Öleis von bis zu  22V Bei einer 't' daff der Strom I hockstens +i e To transmit a ''0'', the decoder must supply a current 1 of 30+4/-6 mA with a voltage drop at the track of up to 2.2V. To transmit a ''1'', the current 1 must be at the most +/- 0.1mA. The power source of the decoder must be protected from unexpected external voltage at the track during the cutout. Figure 2 shows a possible hardware design. Explanation of the Circuit Illustratoin Der RailCom – Teil besteht nur aus den Widerstanden R1 bis R3 und den Transistoren T1a bis T2b. T1a und T1b bilden eine Stromquelle. T2a ist als Diode geschalitet und schütz die Stromquelle vor positiven Spannungen höher Voc. Alle anderen Teile der Schaltung gehören zur normal notwendigen Hardware des Decoders. Man beachte den äußest geringen Hardwareaufwand für den RailCom - The RailCom part consists only of the resistors R1 to R3 and the transistors T1a, T1b, and T2b. T1a and T1b form a power source, T2a is connected as a diode (clipping diode) to protect the power source against higher Vcc voltages. All of the other parts of the circuit are part of the normally necessary hardware of the decoder. It is important to note the extremely low hardware requirement for the RailCom transmitter.
2.3. The RailCom Detector
Ein Detector muss einen Strom von größer 10mA während der mittleren 50% der Bitzeit als 'O' interpretieren, einen Strom von kleiner 6 m darf 200mV bei maximal 34 mA während des Cutout nicht übersteigen. Abbildung 3 zeigt A detector must interpret a current of greater than 10mA during the middle 50% of the bit time as “0”, a current smaller than 6 mA during the middle 50% of the bit time as "1". The voltage drop over the detector may not exceed 200mV at a maximum current of 34 mA during the cutout. Illustration 3 shows a possible hardware design. Figure 3: Example of a circuit diagram for a simple RailCom detector Der Spannungsabfall über dem Cutout Device darf 10mV bei maximal 34 mA während des Cutout nicht übersteigen Es dürfen maximal zwei Detectoren (incl, des globalen Detectors) in Reihe verwendet werden, wobei der lokale Detector egung enthalten solite. Ist dies nicht der Fall, mussen extern The voltage drop at the cutout device during the cutout must not exceed 10mV at the maximum current of 34 mA. A maximum of two detectors (including the global detector) can be used in series whereby the local detector should contain a connection for external evaluation of track occupancy. If this is not the case, the externally used occupancy detector must be specified for RailCom. 5 Ohm, die parallel zum Messwiderstand des Detectors liegen. Der Wert von 5 Ohm entspricht bei einer Gleisspannung von 15V einem Strom Glühlampen (Kaltleiter) sind immer über einen schnellen Brückengleichrichter (<500ns) zu betre
Explanation:
These circuits (transmitters and detector) were tested on large club layouts up to a distance of 100m. Communication over this distance was problem-free. Consumers of 5 ohms, not isolated from the track through a bridge electric rectifier, are allowed parallel to the resistor of the detector. The value of 5 ohms corresponds to a current of 3A at a track voltage of 15V. Simulating bulbs (PTC resistors) must always be operated over a fast bridge electric rectifier (<500ns).
2.4. Timing
In einem Cutout können bis zu 8 Byte Daten übertragen werden. Jedes übertragene Byte beginnt mit einem Startbit ( 0 ) den 8 Datenbits (niederwertigstes Bit zuenst) und endet tinem Stopbit (*1*). Die Obertragungsrate ist 250 kbit's +/- 2%. Die Anstiegszett (10% -- 90%) und Abfallzet (90% --+ 10%) darf 0.5 μs richt doersch Das RailCom Cutout ist in zwei Kanale untertellt. Im Kanal 1 konnen 2 Bytes, im Kanal 2 bis zu 6 Bytes übertragen werden. Abbibung 4 zeigt das Timing Diagramm. Samfiche Zeiten sind auf den Null-Durchgang des letzten Flankenwechsels des Packet End Bits bezogen. During a Cutout, up to 8 bytes of data can be transmitted. Each transferred byte begins with a start bit ("0") followed by 8 data bits (least significant bit first) and ends with a stop bit ("1"). The data transmission rate is 250 kbit/s ± 2%. The rise time (10% → 90%) and fall time (90% → 10%) may not exceed 0.5 μs. The RailCom cutout is divided into two channels. In channel 1, 2 bytes can be transferred. In channel 2, up to 6 bytes can be transferred. Figure 4 shows the timing chart. All times are
Bemerkung Obige Abbildung zeigt das RailCom Timing mit „1“-Bits von 2*58μs (Nominalwert des DCC *1“-Bit). Bei kürzeren „1“-Bits ist es möglich, dass das Cutout ins 5. „1“-Bit hineinreicht. Dies ist aber kein Problem, da eine Zentrale mindestens 4+12=16 Präambelbits senden muss (Stopbit des vorherigen DCC-Pakets nicht mitgezählt), der Decoder also ausreichend Präambelbits (mindestens 11;  10 sind notwendig) sieht. Eine Cutout-Zeit von ca. 450μs darf die Funktion eines Decoders, der RailCom nicht beherrscht, nicht beeinflussen, da auf einer realen Modellbahnanlage Stromunterbrechungen bis 20ms nachgewiesen wurden, d.h. ein Decoder solite mindestens eine Stromunterbrechung in dieser Größenordnung verarbeiten können. Remark: The above illustration shows the RailCom timing with "1" of 2*58μs (the nominal value of the DCC ''1'' - bit). With shorter ''1'' bits, it is possible that the cutout extends into the 5th ''1''- bit; however, this is no problem, since a command station must send at least 4+12=16 preamble bits (the stop bit of the previous DCC packet is not counted in this), so that the decoder sees sufficient preamble bits (at least 11; 10 are required). A cutout - time of approx. 450μs -  must not affect the function of a decoder, which does not implement RailCom, since in an actual model railway layout, current interruptions of up to 20ms have been observed, i.e., a decoder should be able to process at least one current interruption of this size.
2.5. Data Protection
Die Sicherung der Datenúbertragung erfolgt via 4/8 Codierung, d.h. jedes úbertragene Byte enthált 4 *1'- und 4 '0'-Bits. Ist dieses Verháltnis verletzt, liegt ein Übertragun Es gibt 70 verschiedene Bikombinationen innerhalb eines Bytes, de dieses Verhaltinis 4:4 aufweisen. Davon werden 64 for die Übertragung von 6 Nutzbits verwendet, von den 6 
 Es lassen sich in Kanal 1 netto 12 Bit, in Kanal 2 netto bis zu 36 Bit Nutzdaten übertragen. Die möglichen Codierungen: Securing data transmission occurs through 4/8 coding, i.e., each transmitted byte contains 4 'l '- and 4 '0' bits. If this ratio is disturbed, a transmission error has occurred. There are 70 different bit combinations in a byte that exhibit the ratio of 4:4. Of these, 64 may be used for the transfer of 6 payload bits; of the 6 remaining ones, 3 are used for short special messages, ACK, NACK, and BUSY. The remaining three combinations are currently not in use. In channel 1, 12 bits net, and in channel 2 up to 36 net bits of payload can be transferred. The possible codes are listed in Table 2:

3.
Packet Layer
Dieses Kapitel beschreibt den Aufbau von RailCom-Pake t) haben eine Länge von 6, 12, 18 oder 36 Nutz-Bits. Somit ergeben sich für die beiden Kanäle fo RailCom Pakete (im folgenden mit Datagramm bezel This chapter describes the structure of RailCom packets. RailCom packets (in the following table described as datagrams) have a length of 6, 12, 18, or 36
Other possibilities are not approved. Datagramme (außer ACX/NACX/BUSY) beginnen, wenn nicht anders eritutert, mit einem 4 Bit Identifier, gefolgt von 8, 14 oder 32 Bit Nutzdaten Datagrams (except for ACK / NACK / BUSY) begin, unless otherwise explained, with a 4-bit identifier followed by a transfer of 8, 14, or 32 bits of useful data, as follows:
Table 4: Datagram-StructureDie Länge des Datagramms ist durch den Identifier bestimmt. Die Identifier werden weiter unten definiert. Mobile Decoder (LokDecoder) und stationare Decoder (AccessoryDecoder) haben unterschiedliche  Rückmeldeanforden rschiedlich genutzt. Die Bedeutung der Datagramme ist somit abhangig von der Adresse des vorangestelten DCC Pakets. de alle Decoder dechermaßen effillen mössen. Für diesen Zweck wird die DCC-Adresse 255 als "Systemadresse" from 
Befehisarten MOB (mobil) und STAT (stationar) anhand der DCC The length of the datagram is defined by the identifier. The identifiers are defined below (exception: IDO has two different lengths). Mobile decoders (locomotive decoders) and stationary decoders (accessory decoders) have different acknowledging requirements. Accordingly, the channels for both decoder types are used differently. The meaning of the datagrams thus depends on the address of the preceding DCC packet. In
addition, there are system requirements that all decoders must fulfill equally. For this purpose, the DCC address 255 is specified as "system address". The following RailCom instruction types MOB Auf andere Adressen sowie auf Service Mode Pakete dürfen Decoder keine Rückmeldung senden. To other addresses, as well as to service-mode packets, decoders may not send an acknowledgment.
3.1. RailCom Instruction Type MOB
obile Decoder zur schnellen Lokalisierung auf der Anlage (siehe app:adr). Dazu mûssen sie nach Die folgenden Identifier (Datagramme) sind für mobile Decoder definiert: Channel 1 is used by mobile decoders for fast identification of location on the model railroad (see app: adr  low and adr  high). For this process, they must send their DCC address after each of the DCC packets that are sent to the mobile decoder. The address is then received by the local detectors connected to the layout. Exempt are the service mode packets from the time at which the decoder recognizes their service mode. Channel 2 may be used only by the addressed decoder and serves to transmit decoder information. An addressed decoder must always send a feedback signal in channel 2 (if necessary ACK/NACK/BUSY) to confirm the error-free reception of the DCC packet. A feedback signal in channel 2 indicates that the decoder received the instruction error-free, but not that the command was accepted and successfully executed by the decoder.
"Required" requires complete implementation "optional": requires either complete implementation or partial implementation with the conditions specified under section 4.1 erkung ne Identifier belegt, die jetzt als "nicht t Altere Decoder ohne Versions Remark: Older legacy decoders use different identifiers, which are now marked as "Not Approved". Newer decoders must have registered the RailCom version number in a special configuration variable (CV) (see section "RailCom CVs"). The version number can be used for differentiation. You should update older decoders without a version number or have them updated.
3.2. RailCom Instruction Type STAT
eschlossen. Alle Angaben dazu sind als vorlaufig zu be Ortsfeste Decoder nutzen Kanal 1 zur Meidung von Service Request Anforderungen (siehe app;srg). Dazu konnen sie in iedem an einen ortsfesten Decoder gerichteten DCC Pake ihre Identitat (12-Bit Adresse) senden (12 Bit West ohne Identifier !!) (Nicht bei Adressierung via Decoder ID). Melden sich mehrere Decoder gleichzeitig muss eine Such Kanal 2 darf nur yom adressierten Decoder benutzt werden und die nt zur Übermittlung von Decoderinformationen. talls ACK) um den tehlertre Eine Rückmeldung im Kanal 2 signalisiert, dass der D der den Befehl fehlerfrei empfangen hat, nicht jedoch dass der Befehl vom Decoder Die folgenden Identifier (Datagramme) sind für stationäre Decoder definiert: The RailCom specifications for stationary decoders are not yet final. All information herein is to be regarded as provisional. Stationary decoders use channel 1 for reporting service request requirements (see app srq). For this, they can transmit in each DCC packet addressed to the stationary decoder's address (12-bit address) (value of 12 bits without an identifier!!) (Not if addressed via decoder ID). If multiple decoders respond simultaneously, a search must be started. Channel 2 may be used only by the addressed decoder and serve to transmit decoder information. An addressed decoder must always send a feedback in channel 2 (if necessary ACK) to confirm the error-free receipt of the DCC packet. A feedback signal in channel 2 indicates that the decoder received the instruction error-free, but not that the command was accepted and successfully executed by the decoder.
"zwingend" bedeutet volistandige Implementierung "optional": entweder volistancige Implementierung oder: teilweise Implementierung mit den unter 4.1 genannten Bedingungen "mandatory" means full implementation "optional": either full implementation or partial implementation with the conditions mentioned in section 4.1
4.

4.1. System Requirements
er) mit Hilfe der verlangerten "0" (stretched zero) ist nich coder mit RailCom Implementierung muss folgende Ejgenschaften zwingend unterstützen; Wird eine RailCom-CV nicht unterstützt, muss beim Auslesen der Wert üxFF als Antwort zurückgegeben werden This RailCom specification has been developed to be backward-compatible with traditional DCC, i.e., decoders that are not RailCom-enabled can continue to operate on RailCom layouts, and command stations that are not RailCom-enabled can continue to control RailCom-capable decoders. The control of analog locomotives (locs without decoders) with the help of the extended "0" (zero stretched) is not approved. All decoders that contain RailCom implementation must completely support the following mandatory functions: APP.ADR; APP.POM; ACK, NACK, and BUSY The decoder has to provide an answer in channel 2 to each blanking interval (see applications). Any additional RailCom features that are not implemented in the decoder must clearly be answered as such. That means in detail: all RailCom functions that are triggered by a DCC command (a DCC packet), but are not implemented, must be answered with a NACK. If a RailCom CV is not supported, the value 0xFF must be returned as the response.
4.2. CVs
4.2.1.

Table 8: CV28 Railcom Configuration
4.2.2.
CV29
Verwendung nach NMRA S-9.2.2 Bit 3. RailCom use is specified in NMRA S-9.2.2, bit 3.
4.2.3.
CV31, CV32
Verwendung als Pointer nach NMRA S-9.2.2. RailCom use of extended CVs is defined in NMRA S-9.2.2.
4.2.4.
RailCom Page
CV31 = 0 und CV32 = 255 adressieren eine Page von 256 CVs, die für RailCom-Anwendungen nach folgender Tabelle belegt sind: CV31 = 0 and CV32 = 255 address a page of 256 CVs, which are allocated for RailCom
139-255
reserved
Table 9: Allocation page 255 Folgende Werte sind in die CVs 132, 134 und 136 nach Bedarf einzutragen und kennzeichnen den Behältertyp The following values are to be entered in CVs 132, 134, and 136 as needed and identify the type of container:
Table 10: Container types The four most significant bits are not approved for use.
4.3. DCC Commands
Die erweiterte Funktionalität durch RailCom bedingt auch zusätzliche DCC-Befehle. Dazu gehören: Extended functionality by RailCom requires the definition and use of additional DCC commands. The following sections describe the use and functionality of the additional DCC commands.
System Commands
4.3.1.
Systemkommandos werden über die Adresse 255 (üxFF) übertragen. Diese Adresse ist nach NMRA dem Idle-Packet vorbehalten. Als Systemkommando ungleich 0 verwendet. Die Werte, die ben, werden noch publiziert. RailCom system commands are transmitted using the 255 (0xFF) DCC address. This address is reserved for the idle packet per the NMRA DCC standards. The 2 nd byte of the DCC idle packet with a value of unequal (≠) 0 (0x00) is used. The values, which describe the individual commands, will be published later.
4.3.2.
Additional Function Commands
Durch RailCom ergeben sich zustiziche Funkfootsmogichkeiten wie z ß. Suchfunkfon, Befüllen, etc (sishe auch unter Abschnit "Applications (Application instruction" (110) gema RailCom provides additional functional possibilities; for example, the search function, filling, etc. (see also, section "Applications (application/ APP) Layer for Mobile Decoder"). For this purpose, the "Feature Expansion Instruction" ( 110 ) "binary state control instruction short form" is used in accordance with NMRA S-9.2.1: Instruction: binary state control instruction short form V 11011101 DLLLLLLL LLLLLL marks the function code from 1 to 127 LLLLLL = 0  schaltet o.g. Funktionen aus = 0 switches the above mentioned functions off D = 1: Function activated = 0: Function deactivated See also, S-9.2.1. Diese Befehle werden mit XF1 bis XF127 bezeichnet. These instructions are defined as XF1 to XF127.

Extended Programming Instructions
4.3.3.
S-9.2.1 defines a "short form" for programming CV(s) with the instruction "111CCC" 0 DDDDDDD (0 DDDDDDD), where CCCC specifiies which CV(s) to write to. The following data bytes DDDDDDD (DDDDDDD) are then written into the CV(s) that is (are) defined in that way. By extending this allocation, two CVs are defined at the same time This increases security and simplifies the reprogramming of the long address (extended address). CCCC = 0000, 0010, 0011, and 1001 are reserved; the rest is available. Additional allocations: CCCC = 0100 writes to CV17 and CV18 (extended address) simultaneously, and sets bit 5 in CV29. CCCC = 0101 writes to CV31 and CV32 (index high (31) and low (32) byte).
4.3.4.
NOP for Accessory Decoders
der melden sich nach einem Schaltbefehl, wenn sie der Zentrale etwas mitteilen wollen (SRQ) Üblicherweise werden Schaltbefehle aber nur sporadisch gesendet, also könnten sich Accessory Decoder nur ebenso setten bemerkbar machen. Deshalb wird der NO führt, der regelmaßig gesendet wird, aber zunächst nichts bewirkt, außer ortsfesten Decodern ein SRQ zu ermoglichen Dieser muss von allen nicht RailCom-fahigen Basic und Extended Accessory-Decodem als ungültig erkannt und damit ignoriert werden. Er dient zum einen dazu, es Zubeho Decodem zu ermoglichen, in der nachfolgenden Austastlücke einen SRQ abzusetzen, zum anderen eriaubt er für den Fall, dass sich mehrere Deco nelden, auch die Suche nach den beteiligten Decodern. Dies wird dadurch erreicht, dass mit dem NOP eine Accessory Adresse übertragen wird. Es melden sich daraulhin nur diejenigen Decoder, deren Adresse kleiner oder gleich ist w die im NOP enthaltene. Dadurch kann bei Meldungen von mehreren Decodem mittels sukzessiver Approximation der De und bedient werden. Die Suche wird solange wiederholt, bis sich kein Decoder mehr meldet, Instruction: NOP for accessory decoders Pbl 0 1 0 A10 A9 A8 A7 A6 A5 0 0 A4 A3 A2 1 A1 A0 T 0 EEEEEEE 1 A10...A0 = Accessory Adresse (lineare Adressierung)3
T = 0 A10...A0 ist eine Basic Accessory Decoder Address = 1 A10...A0 ist eine Extended Accessory Decoder Address T wird für die Suchfunktion als hochstwertiges Adressbit betrachtet (A11) EEEEEEE XOR Prüfbyte Für die regelmäßige Abfrage aller Accessory Decoder sendet die Zentrale sinnvollerweise ein NOP mit der höchstmöglichen Adresse, damit alle Decoder an Solange sich hierauf immer nur ein Decoder mit einem SRQ meldet, kann es bei diesem NOP mit der hochsten Adresse bleiben. Erst, wenn sich mehrere Decoder gi melden, muss die Zentrale eine Suche starten, indem sie die im NOP enthaltene Adresse geeignet variert. Eine RailCom-fahige Zentrale muss zur Abrage der Accessory-Decoder in bestimmten Zetabständen einen NOP-Befehl senden. Der zeitliche Abständ zwischen zwei NOP's ist ein noromiss aus Bandbreteneinschrankung beim DCC-Signal und Reaktionszeit auf SRO-Meldungen. Es wird ein Intervall von ca. 0.5 Seku Bei Suchvorgangen nach Mehrfachmeldungen müssen die zur Suche verwendeten NOPs natürlich schnellstmöglich hintereinander gesendet werden Accessory decoders report their status after receiving a switching command or when the command station requests a status request (SRQ). Normally, switching commands are sent sporadically, so accessory decoders could make themselves known equally rarely. Therefore the NOP command was introduced that is sent regularly, but does nothing except to allow a stationary decoder a cutout window in which to transmit its status. The SRQ must be recognized by all non-RailCom-enabled basic and extended accessory decoders as not valid and therefore be ignored. It serves first to enable accessory decoders in the subsequent blanking interval (blanking period) to deposit an SRQ, and secondly, in case that several decoders respond with an SRQ at the same time, also permits a search for participating decoders. For the NOP command to be effective, the NOP command transmits an accessory decoder address with its transmission. Only those decoders repond whose address is smaller or equal to the address contained in the NOP. Then, as messages from several decoders arrive by successive approximation, the decoder with the lowest address can be found and served. The search is repeated until no decoder responds any longer.. Instruction: NOP for accessory decoders A Preamble 0 10A 10A 9A 8A 7A 6A 5  0 0A 4A 3A 2 1A 1A 0T 0 EEEEEEE 1 = Accessory address (linear address) 3 A10 … A0 T = 0 A 10 ... A 0 is a basic accessory decoder address A 10 ... A 0 = 1 A 10 ... A 0 is an extended accessory decoder address T for the search function is regarded as the most significant address bit (A μ ) EEEEEEE XOR checksum byte ³ The linear encoding is going to be adjusted to the extended accessory coding per S-9.2.1. The statement there is not clearly formulated. Adjusted as soon as the Standard is clarified. For regular monitoring of all the accessory decoders, the command station sends a NOP with the highest possible address so that all decoders are addressed. As long as only one decoder responds with an SRQ, the NOP with the highest address remains. Only when multiple simultaneous decoders notify the command station, the command station must start a search by varying the address that is contained in the NOP appropriately. A RailCom-enabled command station must query the accessory decoder periodically by sending a NOP command. The time interval between two NOP commands is a tradeoff between bandwidth limitation at the DCC signal and response time to SRO messages. We recommend an interval of 0.5 seconds. Searches to multiple messages require of course that the NOP commands used to search are sent as quickly as possible one after the other.
5.

Die nachfolgenden Abschnitte beschreiben die Befehle für die RailCom-Funi Die Befehle von der Zentrale zum Decoder ( ▷ ) sind jeweils ohne die Adressierungs-Daten notiert. Die Adressierung erfolgt nach dem DCC-Standard. Befehle, die voliständig no sind kennzeichnen sich durch die Angabe der DCC-Preamble (pbf). Diese Pakete werden nach DCC-Standard mit einem Nuli-Bit (0) zwischen den übertragenen Bytes, einer XOR- Checksumme (CHK) und einem Eins-Bit (1) am Ende des ●) kennzeichnet die gesendeten RailCom Wenn nicht anders angegeben, beziehen sich Werte rangestelltes Ox gel The following sections describe the instructions for RailCom functionality. The instructions from the command station to the decoder ( ► ) are noted in each case without the addressing data. Addressing utilizes the DCC standard. Commands, which are completely noted, are indicated by the DCC preamble {pbl}. According to the DCC standard, these packets are equiped with a Null-bit (0), between each of the transferred bytes, a XOR Checksum (CHK), and a 1-bit (1) at the end of the packet. ( ●) indicates the sent RailCom data. If not indicated otherwise, values always refer to an 8-bit field. Binary values are indicated by a placing of 0b in front of the value. Hexadecimal values are indicated by a placing 0x in front of the value.
5.1. Programming on the Main (POM)

with V=CV Address and D=CV data. Wenn die CV-Adresse im Bereich 257 bis 512 ist, wird immer und automatisch die indizierte CV-Adressierung mit Hilfe von CV31 und 32 benutzt. When a CV address is in the range of 257 to 512, the indexed CV addressing with the aid of CV31 and CV32 is always and automatically used. The following modes are defined
Table 12: POM modes
5.1.1.
Read 1 Byte
Operation Mode Instruction: POM Read Byte
△
1 Channel 2 (12-bit): 0b0000 (ID0) DDDDDDD with V=CV-Address and D=CV-Data. Das zugehörige Antworldatagramm (IDO) muss nicht im selben Packetframe gesendet werden, sondern kann zu einem soateren Zeitpunkt erfolgen. Eine erbefehl gesendet wird (der gle siert wird und vorher kein an che ist erlaubt). Auf Lesezugriff antwortet der Decoder mit "BUSY", so lange der Vorgang nicht abgeschlossen ist. Wenn der Lesevorgang beendet ist, sendet der Dec der nicht innerhalb von 0,5s die Daten zurück dann gilt der Lesevorgang als fehlgeschlagen sfehl das Eroebnis. Gibt der Decod The corresponding response datagram (IDO) must not be sent in the same packet frame, but can be sent at a later time. A command station must therefore ensure that the decoder is addressed once more before any other programming command is sent (the same is allowed). The decoder responds to read access with "BUSY", as long as the operation is not completed. When the read operation is completed, the decoder transmits the result on the appropriate, renewed re-read command. If the decoder does not return the data within 0.5 s, the operation is considered failed.
5.1.2.
Write 1 Byte
Operation Mode Instruction: POM Write Byte △ 111011VV 0 VVVVVVVV 0 DDDDDDD ・ Channel 2 (12-bit): 0b000 (ID0) DDDDDDD hier wird der Wert zurückgeschickt, der NACH der POM Operation in der CV vorhanden ist. Here the value of the CV is sent back that is present in the CV AFTER of the POM operation. Note: V=CV address and D=CV data. Auf Schreibzugriff antwortet der Decoder mit "BUSY", so lange der Vorgang nicht abgeschlossen ist. Der Decoder vergleicht die erhaltenen CV-Daten mit den Daten und sendet engebnisablang ein ACK oder NACK. Die Zentrale wiedenot nach einem "BUSY" den Schreiberehi so lange, bis der Decoder mit "ACK" of
glit der Schreibvorgang at The decoder responds to a write access request with "BUSY", as long as the operation is not completed. The decoder compares the received CV data with the CV-written data and sends a result-dependent ACK or NACK. After a "BUSY" message, the command station repeats the write command until the decoder responds with an "ACK" or "NACK". The command station must not send any other command during this time to this decoder. If the decoder does not respond within 0.5 s with an "ACK" or "NACK", the write operation is considered to have failed. In a read-only CV, the decoder provides the current value of the CV.
5.1.3.
Write Bit
Operation Mode Instruction: POM Write Bit
With V=CV address and D=CV data und B=bit position {0-7}. Antworten wie bei "Write Byte". The answers are the same as with "Write byte".
5.1.4.
Read 4 Byte

Der POM-Befebl wird dahingehend In order to be able to read multiple CV in as short a time as possible, an additional read command was introduced. The POM-command was changed so that the previously unused bit-combination CC = 00 is now used. This new command starts a read operation, during which the decoder returns 4 bytes.
Operation Mode Instruction: POM
△
1 Channel 2:(36 bit) 0b0000 (ID0)  (ID8-9) DDDDDDD  DDDDDDD DDDDDDD  DDDDDDDD with V=CV address and D=CV data. Die Antwort kommt in einem 38-Bit Datagrammen mit der IDO d.h. ess reprien steds 4 aufeinanderfolgende CV-Werte (über autoing Das zugehorige Antworldataoramm (IDO) muss nicht im selben Packetframe gesendet werden, sondern kann zu einem soateren Zeitounkt Auf Lesezugriff antworlet der Decoder mit "BUSY", so lange der Vorgang nicht aboeschlossen ist. Wenn der Lesevorgang beendet ist, sendet der I fehl das Ergebnis. Gibt der Decoder nicht innerhalb von 0,5s die Daten zurück dann gilt der Le Den Zusammenhang zwischen über den Index aus CV31 undCV32 adressierten und den bisherigen 1024 CVs liefert fol The answer comes in a 36-bit datagram with the IDO, i.e., always 4 successive CV values are returned by using autoincrement. The corresponding response datagram (ID0) cannot to be sent in the same packet frame, but can be sent at a later time. A command station must ensure that the decoder is addressed again and no other command is sent to this decoder until the read operation is complete. Sending the same command again is allowed. The decoder must be responds to read access with "BUSY", until the operation is completed. If the read operation is completed, the decoder transmits the result after an appropriate, re-read command. If the decoder does not respond within 0.5s, the data read back is considered failed. The relationship between the previous 1024 CVs and the CVs addressed with the index from CV31 and CV32 is provided in the following table:
Table 13: Relationship between standard POM command and indexed POM command
5.2. ADR

Consist). Hierfür werden die folgenden 12-Bit Datagramme mit ID1 und ID2 d Mobile decoders use channel 1 as a broadcast channel for its own address. In the cutout, after each DCC packet addressed to a mobile decoder, a mobile decoder sends a packet with its active address (Primary, Extended, or Consist). For this address, the following 12-bit of datagrams with ID1 and ID2 are defined:
Table 14: ADR allocation address Ein Decoder muss abhtingig von seiner aktiven Adresse die beiden Datagramme ADR1 und ADR2 alternierend senden. Die "aktive Adresse" ist die, unter der Deco Fahrbefehle erhalt A decoder, depending on its active address, must alternatingly send the two datagrams ADR1 and ADR2. The "active address" is the decoder's address, under which the decoder responds to speed and direction commands.
Mogliche Anwendung Lokale Detectoren (Local Detector) auf der Aniage werten diese Datagramme zeitnah aus und senden dies Dieses Verfahren eignet sich besonders zur Zugb Possible application: Local detectors (Local Detector) on the layout near the mobile decoder evaluate these datagrams and promptly send this information back (command station, computer etc.). In this way, the command station can determine which decoder is on a particular section of track. Figure 5 shows this schematically. This method is particularly suitable for automatic train control. Figure 5: Local information of mobile decoders Die Lokalisierung eines Decoders nach obigen Muster kann nur funktionieren, wenn der Decoder sich alleine auf dem vom Local Detector überwachten Gleisabschnit befindet genden Loks Problematisch is des indoch in Multinakionsbetries. Herful with employen, dass nur die führende Lok de ADR-Datagramme auf Kanal 1 sendet, während bein fölling 
diese Funkio The local information of a decoder using the above approach can only function if the decoder is alone on the track section that is supervised by the local detector. This approach becomes problematic when multiunit or consists are utilized. In this case, it is recommended that only the first locomotive in the consist sends the ADR datagrams on channel 1, while this function is deactivated via CV28 for the following locomotives. This can happen by arranging the consist using POM.
5.3. EXT

5.3.1.
Sending Local Information
Die Ortsinformation kann durch den Decoder oder den Detector gesendet werden, ie nachdem, wo die Information vprilegi Fall 1: Ortsinformation liegt im Deco Fall 2: Ortsinformation liegt im Detector von The local information can be sent by the decoder or the detector, depending on, where the information is located. Case 1: Local information resides in the decoder (e.g., through infrared transmission). Case 2: Local information resides in the detector.
Operation Mode Instruction Reply: EXT
△ pbl-0-(locomotive address)-0-11011101-0-0000001-0-XOR-1 Case1: Local information is present in the decoder (e.g., by infrared transmission) ▲ Channel 2 of the decoder 0b0011 (ID3) 0b00 0bZZZZOOOOOO ZZZZ = 0000: Local information ZZZZ = 0001- 1111: not approved for use 00000000: 8-bit location address Case 2: Local information is present in the detector +
en RailCom-Sender ergänzt . Da die Ortsinformation über das Gleis zurück gesendet wird, ist k Der Detector funktioniert wie in Figure 5, wird abe The detector functions as in figure 5, but is supplemented by a RailCom transmitter. Since the local information is sent back over the track, no further connection is necessary to the detector, e.g., a bus system.
5.3.2.
Filling
Operation Mode Instruction Reply: XF-Instructions
A pbl-0-(Locomotive address)-0-11011101-0-DLLLLLLL-0-XOR -1 Channel 2 of the decoder: 0b0111 (ID7) 0bDDDDDDXXXXX (see 5.4Table 15: Search and filling order DYN) Beim Befüllen sendet die Zentrale den Fülbefehl XFn. Daraufhin sendet der Decoder bevorzugt den Behälterinhalt in Kanal 2 zurü leichzeitig empfängt der Detector diesen Befehl, vergleicht die Lokadresse des DCC-Packets mit der in Kanal 1 empfängenen I tie Adressen gleich und der Fülbefehl stimmt mit dem Typ der Befüllungsanlage überein, dann startet der Befüllvor Der Detector verandert die Gleissymmetrie mit der Geschwindigkeit (Frequenz), die im Detector für das Befüllen abgelegt ist Der Detector benotiqt folgende Einstellmoglichkeiten: Ortsadresse (1-256), Behältertyp (2 – 15) und Füllgeschwindigkei Der Wertebereich der Füllgeschwindigkeit beträgt 1-255, dieser Wert verdoppelt ergèt die Füllzeit auf 100% Füllung in Sekunden. Die niedrigste Frequenz für 2 Sekunden Füllze itten von 1% ist dann 50Hz. Im Detector wird die Art des Befüllens mit der gleichen Dezimalzahl abgelegt, wie sie bei den Behältertypen in den RailCom CVs benützt werden (siehe Die Füllung kann nur bei Geschwindigkeit=0 vorgenommen werden und wird immer durch einen Fahrbefehl mit Geschwindigkeit >0 oder durch D=0 im XF-Befehl beendet. "LLLLLL" kennzeichnet die Such- oder Füllauftrag: When filling, the command station sends the filling instruction XFn. The decoder sends back the tank capacity in channel 2. At the same time the detector receives this command and compares the locomotive address of the DCC packet with the locomotive address received on channel 1. If not equal, nothing happens. If the addresses are the same and the Fill command matches the type of filling system, then the filling operation starts. The detector changes the track symmetry with the speed (frequency), which is stored in the detector for the filling. The detector needs the following adjustment possibilities: Location address (1-256), type of container (2 - 15) and filling speed. The range of values for the filling speed is 1-255. Doubling this value provides the filling time for 100% filling in seconds. The lowest frequency for 2 seconds of fill time in increments of 1% is then 50 Hz. The detector stores the manner of filling with the same decimal number as it is used in the container types in the RailCom CVs (see section 4.2). Filling can only occur only when speed = 0 and is always terminated by a command to move with speed > 0 or by D = 0 in the XF command.
Table 15: Search and filling order
5.4. DYN

Die Übertragung von dynamischen Variablen (DV) (z.B. Geschwindigcett Behalter, ...) erfolot in einem 18 Bit Datagram (D7), welches den 8 Bit Wert der DV (D) s 2 beliebige DVs können in einem Rückmeldeframe übertragen werden. Welche DVs ein Decoder wann sendet bestimmt er selbst The transmission of dynamic variables (DV) (e.g., speed, containers,…) takes place in an18-bit datagram (ID7), which contains the 8-bit value of the DV (D) as well as 6-bit subindex (X), which select a specific DVs out of possible set of 64. The importance of the DV is set by the subindex. Two arbitrary DVs can be transferred in an acknowledging frame. The decoder decides which DVs are to be sent.

5.5. sublD
Die sublD gibt Lizenznehmern die Möglichkeit, neue RailCom Features zu entwickein, zu testen und in Produkte zu imple Dazu bekommt der Lizenznehmer vom Lizenzneber (Lenz Elektronik GmbH) eine Nummer zugeteilt, die in die CV138 der RailC ch verschiende Applikationen voneinander unterscheid Der Lizenznehmer verpflichtet sich dem Lizenzgeber das Entwicklungsziel zu nennen und bei Fertigstellung der Ent Spezifikation für die anderen IDs praktiziert) zur Verfügung zu stellen. Der Lizenzgeber wird die Nummernvergabe und die Ziele, wie auch die Beschreibung des fertigen Produktes in Abs publizieren. Dadurch wird es anderen Lizenznehmern ermöglicht, diese Entwicklung ebenfalls zu nutzen The subID gives licensees the opportunity to develop new RailCom features to develop, to test, and to implement in products. The Licensor (Lenz Elektronik GmbH) provides the licensee with an assigned number, which is stored in CV138 on the RailCom page. This number helps differentiate different applications from each other. The Licensee agrees to provide to the licensor with the development goal and to provide a detailed description (as documented in this specification for other IDs) on completion of the development. The Licensor publishes the number assignment and the objectives, as well as the description of the finished product in consultation with the Licensee (e.g., post-marketing). This will allow other Licensees to also use this development. [Although NMRA can issue the initial license to the Licensee, based on the contents of this Standard , subsequent application modifications by the licensee must be approved by Lenz Elektronik GmbH.]
6.
Application for Stationary Decoders (Switches, etc.)
6.1. SRQ
Zweck Service Request für ortsfeste Decoder Der Kanal 1 des Cutouts wird von ortsfesten Decodem benutzt, um die Zentrale zu einer Kommunikation zu veraniassen. Diese Aufforderung wird im folgenden als SRQ (Service Request) bezeichnet. Der SRQ kann entweder nach einem beliebigen Accessory Packet gesendet warden (gleichgültig weiche Adresse damit angesprochen wird und gleichgültig, ob es ein Basic ode Extended Accessory Control Packet ist) oder nach einem NOP, wenn die eigene Adresse kieiner oder gleich der im NOP enthaltenen ist. (Vgl. Kapitel 4.3.4) Bei einem SRQ nach einem NOP ist de entsprechende Meidung in Kanal 2 oleich mit zu senden, um etwas Zeit zu sparen. Erfolot der SRQ iedoch nach einem regulaten Acco Befehl, so darf die Meldung nicht gesendet werden, damit die Meldungen des adressierten Decoders nicht unkennsich genacht werden Beim SRQ handelt es sich um ein 12-Bit-Datagramm. Im Gegensatz zu allen anderen Datagrammen enthalt der SRQ keine Kennung, viel mehr werden de 12 Nutzbits zu Übertragung transmission der kompletten Zubehoradresse accessory address herangezogen. It takes more than 12 bits to transmit the full accessory decoder address Operation Mode Instruction: Basic Accessory Control 1 0 A7 A6 A5 A4 A3 A2 0 1 !A10 !A9 !A8 C A1 A0 D
1 0 A10 A9 A8 A7 A6 A5 0 0 A4 A3 A2 1 A1 A0 T Kanal 1: 0b 0 A 10 A 9 A 8 A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 (Basic Accessory Decoder) , , Kanal 1: 0b 1 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 (Extended Accessory Decoder) Kanal 2: den SRQ betreffende Meldung, z. B. Error (nur bei Antwort auf NOP) A Die Bitbezeichnung aus S-9.2.1: 1 0 A7 A6 A5 A4 A3 A2 0 1 !A10 !A9 !A8 C D2 D1 D0 ... A0 = Gruppenadresse des (vierfach-)Decoders D2 ... D1 = Subadresse, paarweise (Weichenadresse) wurde umgewandelt in:
A10 ... A0 = Weichenad resse aus D0 wird D (Auswahl des Ausgangs innerhallo einer Weichenadresse) C besagt, ob der Ausgang ein-(1) oder aus-(0) geschaltet werden soli Durch die Beschränkung der Adressauflösung bei Basic Accessory Decodern auf Ausgangspaare erhält man ebenso wie bei den Extended Accessory Decodern eine 11-Bit und kann dadurch mit dem 12. Bit des SRQ-Datagramm ms zwischen diesen beiden Kategorien un Hat ein Decoder einen SRQ abgesetzt, muss er diesen wiederholen, bis er behandelt wurde. Der Decoder darf in dieser Zeit auf keine an sich gerichteten Stellbefehle reagierer Ein SRQ gilt essential  als than behandelt processed, wenn der Decoder auf der eigenen its own address Adresse einen Löschbefehl erhalten hat. Als Löschbefehl dient der ,Coi der Befehle command als solche nicht ausgeführtp Off"-Befehl bzw. der "absolute stop"-Befehl. In diesem Zustand situation werden die genannten addressed der but bewirken operate  lediglich simply, dass der SRQ nicht mehr gesendet wird not send the SRQ anymore. Löschbefehl für Basic Accessory Decoder: Coil off Format: (pbl) 0 1 0 A7 A6 A5 A4 A3 A2 0 1 !A10 !A9 !A8 0 A1 A0 0 0 EEEEEEE 1 Löschbefehl für Extended Accessory Decoder: Absolute stop (=Asp (pbf) 0 1 0 A10 A9 A8 A7 A6 A5 0 0 A4 A3 A2 0 A1 A0 1 0 0000000 0 EEEEEEE 1 Eine RailCom-fahige Zentrale sendet repelmabig sinen NOP, um SROs zu ermodichen. Empfanot ein Accessory Decoder in den ersten 5 Sekunden nach dem ersten Empfano des DCC-Formates kerne NOPs, so dar er davon a soehen, dass die Zentrale nicht RailCom-fakig ist, somit keine SROs bearbeitet werden konnen und er auch keine senden blocklert.
I Service request for stationary decoders. Purpose Stationary decoders must use channel 1 of the cutout to communicate with the command station when requested to do so. This request is called an "SRQ" (Service Request). An SRQ reply can either be sent after any accessory packets are sent (regardless which address it may address and regardless whether it is a basic or extended accessory control packet) or after a NOP command, if the address is equal to or less than its own address. (Compare chapter 4.3.4) For an SRQ after a NOP command, the appropriate message in channel 2 is sent along at once to save time. However, if the SRQ occurs after a regular asseccory command, the message cannot be sent along, so that the messages of the addressed decoder will not be overwritten. The SRQ is a 12-bit datagram. Unlike all other datagrams, the SRQ contains no identification. Instead, the 12 useful bits are used to transfer the complete accessory address. Operation Mode Instruction: Basic Accessory Controlム. . + 1 ▲
1) The Bit identification from S-9.2.1:! 1 0 A 7 A 6 A 5 A 4 A 3 A 2 A 10 A 9 A 8 0 1 C D2 D1 D0! A 8 ... A 0 = Group address of the (quad) decoder D2 ... D1 = subaddress, pairs (point address) was converted to: A 10 ... A 0 = switch address, from D 0 D (choice of output within a switch address). C indicates whether the output on (1) or off (0) is to be switched By limiting the address resolution with basic accessory decoders, as it is done with extended accessory decoders to output pairs, an 11-bit address is obtained, that therefore, with the 12th bit of the SRQ datagram, can distinguish between these two different categories. If a decoder has stored an SRQ, it must repeat the SRQ until it is processed. During this time, the decoder cannot respond to any adjusting commands sent to it. An SRO is considered processed, when the decoder has received an E-Stop command on its own address. The Coil off command, or respectively the absolute stop command, serves as an E-Stop command. In this state, these commands are not executed, but merely stop sending the SRQ. When an E-Stop command is addressed to an accessory decoder, it is important that the accessory decoder continues to function normally and ceases sending SRQ information. (It does not "stop" operating but just stops transmitting SRQ.) E-Stop command for basic accessory decoder: Coil off Format: {pbl} 0 1 0 A 7 A 6 A 5 A 4 A 3 A 2 0 1 !A 10 !A 9 !A 8 0 A 1 A 0    0    0   EEEEEEE   1 E-Stop for the Extended Accessory Decoder: Absolute stop (Aspect = 0) Format: {pbl} 0 1 0 A 10 A 9 A 8 A 7 A 6 A 5 0 0 A 4 A 3 A 2 0 A 1 A 0 1 0  0000000  0  EEEEEEE  1 Note: A RailCom-enabled command station regularly sends a NOP command to enable SRQs. If an accessory decoder does not receive a NOP command in the first 5 seconds upon being activated with a DCC signal, the decoder must assume that the command station is not RailCom-enabled. Thus, no SRQ can be processed and needs to be sent by the decoder. In this case, the function of the decoder is not blocked.
6.2. POM
Lesen/Schreiben von Konfigurationsvan
lizierte CV-Adressierung mit Hilfe von CV31 und 32 benutz
Purpose read/write configuration variables Operation Mode Instruction: POMム+
with V 9 … V 0 = CV address and D 7 … D 0 = CV data. When the CV-address is in the range of 257-512, the indexed CV addressing with the aid of CV31 and 32 is always and automatically used. The following modes are defined:
Table 17: Modes of POM The relationship between the previous 1024 CVs and the CVs addressed with the index from CV31 and CV32 is provided in the following table:
Table 18: Relationship between the standard POM command and the indexed POM command
6.2.1.
Read 1 Byte
Operation Mode Instruction: POM Read Byte 1 1 1 0 0 1 V9 V8 0 V7 V6 V5 V4 V3 V2 V1 V0 0 000000 Kanal 2 (12Bit); 0b000 (IDO) D7 D6 D5 D4 D3 D2 D1 D0 mit V9...V0 = CV-Adresse und D7...D0 = CV-Dat sendet werden, sondern kann zu einem soateren Zeitounkt erfo
with V ... V o = CV address and D 7 ... D o = CV data. The corresponding response datagram (IDO) must not be sent in the same packet frame, but can be sent at a later time. A command station must also ensure that the decoder is addressed again and that no other command is sent to this decoder. (Sending the same command is allowed.) The decoder must respond with "BUSY" to a read command as long as the operation is not completed. When the read operation is completed, the decoder transmits the result on the appropriate channel after a new read command. If the decoder does not repond within 0.5 s, the process is considered failed.
6.2.2.
Write 1 Byte

abhängig ein ACK odes hach einem "BUSY" den St Bei einer Readonly CV liefert der Decoder den Operation Mode Instruction: POM Read Byte Operation Mode Instruction: POM Write Byte
1 1 1 0 1 1 V9 V8 0 V7 V6 V5 V4 V3 V2 V1 Vo 0 D7 D6 D5 D4 D3 D2 D1 Do Channel 2 (12-bit): 0b0000 (ID0) D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0 Here the value is returned, which is present in the operation NACH oft the POM operation in the CV. with V đ ... V o = CV address and D 7 ... D o = CV data. A write command can be accepted by the decoder only if the command was sent two times. The decoder responds with "BUSY" to write access, so long the process is not completed. The decoder compares the received data with the CV-written data and depending on the outcome, sends an ACK or NACK. The command station repeats thewrite command after a "BUSY", until the decoder responds with an "ACK" or "NACK". The command station must not send another command to this decoder during this time. If the decoder does not respond within 0.5 s with an "ACK" or "NACK", the writing operation is considered to have failed. With a read-only CV, the decoder provides the current value of the CV.
6.2.3.
Write Bit
Operation Mode Instruction: POM Write Bit 1 1 1 0 1 0 V9 V8 0 V7 V6 V5 V4 V3 V2 V1 V0 0 1 1 1 D B2 B1 B0 Kanal 2 (12Bit): 0b000 (ID0) D7 D6 D5 D4 D3 D2 D1 D0 : CV-Adresse, D = CV-Bitdatum und B2 B1 B0 = Bitposition (0-7) Antworten wie bei "Write Byte Operation Mode Instruction: Write bit POM 1 1 1 0 1 0 V 9 V 8 0 V 7 V 6 V 5 V 4 V 3 V 2 V 1 V 0 0 1 1 1 1 D B 2 B 1 B 0 + Channel 2 (12-bit): 0b0000 (ID0) D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0 with V 9 ... V 0 = CV address, D = CV-bit data and B 2 B 1 B 0 = {0-7} bit position D 7 ... D 0 = read back CV data Answers as with "Write Byte".
6.2.4.
Read 4 Byte
i zu können, wird ein zusätzlichen benutzte Bitkombination CC=00 verwendet wird. D Operation Mode Instruction: POM 1 1 1 0 0 0 V9 V8 0 V7 V6 V5 V4 V3 V2 V1 V0 Kanal 2:(36 Bit) 0b000 (ID0) (ID8-9) D7 D6 D5 D4 D3 D2 D1 D0 (aus CV n) D7 D6 D5 D4 D3 D2 D1 D0 (aus CV n+1) D7 D6 D5 D4 D3 D2 D1 D0 (aus CV n+2) D7 D6 D5 D4 D3 D2 D1 D0 (aus CV n+3) it V9 = CV-Adresse n  D7 = CV-Date erden stets 4 aufeinanderfolgende CV-Werte zurückgelier elben Packetframe gesendet werden, sondern kann zu einem soateren Zeitounkt erfolgen. Ei Auf Lesezugriff antwortet der Decoder mit "BUSY", so lange der Vorgang nicht abgeschlossen ist. Wenn der Lesevorgang beendet ist, sendet der Deco von 0.5s die Daten zurück dann gilt der Lesevorgang To succeed in sorting extensive amounts of CVs in the shortest possible time, an additional read command is introduced. The POM command is changed so that the previously unused Bit combination CC = 00 is used. This starts a read operation in which the decoder returns 4 bytes. Operation Mode Instruction: POM v 1 1 1 0 0 0 V 9 V 8 0 V 7 V 6 V 5 V 4 V 3 V 2 V 1 V 0 + Channel 2:(36 bit) 0b000 (ID0) (ID8-9) D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0 (from CV n) D 7 D6 D5 D4 D3 D2 D1 D0 (aus CV n+1) D 7 D6 D5 D4 D3 D2 D1 D0 (from CV n+2) D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0 (aus CV n+3) with V ... V o = CV- address, D 7 ... D o = CV data. The response comes in a 36-bit datagram with IDO, i.e., always 4 successive CV values are returned. The corresponding response datagram (ID0) does not have to be sent in the same packet frame, but can be sent at a later time. A command station must also ensure that the decoder is addressed again and no other command is sent to this decoder (sending the same command is allowed). The decoder responds to a read access request with "BUSY", as long the operation is not completed. If the read operation is completed, the decoder transmits the result on the appropriate, re-read command. If decoder does not respond within 0.5 s, the process is considered to have failed.
6.3. STAT1

Operation Mode Instruction Reply: STAT1 ▶ Operation Mode of Instruction to the decoder address + Channel 2 12-bit: 0b0100 (ID4) 0bDDDDDDD The status code can be sent back as a receipt for accessory commands. An "ACK" can be omitted. First datagram
Table 19: Status Messages, part 1 6.4. TIME Zweck Operation M
ognostizierte Umlaufzeit). Die Zeit wird abhär n Erreichen des Ende-Zustand dieses Begriffes (n lern ohne Glühlampensims
Purpose Transmitting the predicted orbital period Operation Mode Instruction Reply: TIME
This command acknowledgment can be sent back as a receipt after accessory commands. An "ACK" can then be omitted. The 7 least significant bits of the remaining term indicate the running time to reach the end-state of this term (predicted orbital period). The time, depending on the MSB, is indicated in 1/10 seconds (MSB = 0) or 1 second (MSB = 1). A time of 0 means no switching time - for example, at signal decoders without simulating bulbs. This results in a value range from 0-12.7 seconds or respectively... 0-127 seconds. 1. Datagram
Table 20: Projected orbital period.
6.5. ERROR

Operation Mode Instruction Reply: ERROR
A Operation Mode of Instruction to the decoder address (including NOP) 1 Channel 2 12-bit: 0b0110 (ID6) 0bDDDDDDD The error code from the addressed decoder can be sent back, including NOP. An "ACK" can then be omitted.

6.6. DYN

Operation Mode Instruction Reply: DYN . +
The transmission of dynamic variables (DV) occurs in an 18-bit datagram (ID7), which contains the 8-bit value of the DV (D) and a 6-bit subindex (X) that selects one of 64 possible DVs. The importance of the DV is determined by the subindex. Any 2 DVs can be transferred in an acknowledging frame. The decoder determines itself which DVs to send.
Table 22: Dynamic Information
6.7. STAT2
chen Komponenten schon benutzt. Bei anderer Nutzung der ID8 wird die Länge des Datagram cheidungsmerkmal vess Copo Operation Mode Instruction Reply: S Operation Mode Instruction an Decoderad 0b1000 (IDB) 0b000000
Tabelle 23: Statusmeldungen, Teil : STAT2 is not used for new designs, but is already in use in components available on the market. For other uses of the ID8, the length of the datagram is used as a distinguishing feature.
Operation Mode Instruction Reply: STAT2 A
+ Especially designed for mechanical control operations. 1. Datagram