Protocol is normally used for asynchronous communication on a full duplex V.24 interface (RS232), using only data signals RXD, TXD, and ground (3- wire communication).
When a programmer needs to send a datagram from some Siemens equipment over MORSE network, he must send the network layer header prior the data. Receiving process should strip this information from received buffer (there is address of the sender).
| NETWORK HEADER | DATA | DLE | ETX |
| T/8 | R/5 | N/3 | DST/16 | SRC/16 | L/16 | 0000 1001 00000 111 5505 55FF 0002
Network layer data:
| DATA | AAAA
– Packet type
– Reserved, must be zero
– Network number (transferred over the network)
– Destination Address
Length of data field
Packet numbering is not compulsory. Only the lowest three bits from the number are transmitted. The entered number is transported to the destination address, and can serve to control the order of the delivered packets (the MORSE network does not guarantee a perfect order for packets).
The maximum allowable length of data in the MORSE network layer is 1626 bytes. Longer packets are not defined within the system. The optimum packet size for MORSE system is 200-400 bytes.
All 2-byte and 4-byte values are transferred in normal order. The highest byte is transmitted first, and then the lower ones (beware, as the Intel processor format is typically the opposite).
>> 11:45:05.588| |690F5505 690F55FF|S01I IN 2|89 7user AAAA 11:45:05.601 tx 1 | S01 02 11:45:05.610 rx;i 1 | S01 10 11:45:05.611 tx 12 | S01 0907 5505 55FF 0002 AAAA 1003 11:45:05.628 rx;i 1 | S01 10
The data AAAA came from the MORSE system to the SCC1 channel having set the Siemens 3964(R) protocol. The protocol sends the character 02 (=STX) to the link, obtains the character 10 (=DLE) from connected equipment Siemens. Then it sends the frame in Siemens format containing the data AAAA and the characters 1003 (=DLE ETX) on the end. The communication is terminated by receiving the character 10 (=DLE).
Since release 723 the protocol MARS-E was extended to be use as 3963R by Siemens.
MARS-E parameters: (m):3964R (t)arget:0000 (a):400ms (r):1 (s):OFF (b):OFF (p):LOW (q)uit >>
The link layer protocol is always configured using the protocol parameters:
– Protocol 3963R is enhanced to Mars E capability.
– Siemens 3964R mode. Response is send to the last received source address.
– Siemens 3964R mode. Response is send to the configured address by target parameter.
– Destination address. Parameter target is only valid in “3964R Target” mode.
– ACK timeout – the time after transmitting a data frame in which the transmitting station waits for an ACK frame. If the ACK does not arrive, the frame is repeated.
– Number of repeats – if the number of repeats is exhausted and the ACK timeout expires, the network layer is informed that the packet is lost.
– security – obsolete, set off
– Use BRR 3964R compatibility. Don’t escape data with DLE and don’t send final DLE | ETX.
– Priority on the wires. If set to LOW prefer received STX even if STX was already sent. Equipment communicating using the Siemens 3964(R) link layer must have a priority setting in case of collision. Setting: