I'm a newbie in ARINC-429 standard; the following might be a very simple issue for you. In ARINC 429 the LABEL field is covered by the bits 1 through 8; which bits are covering the Equipment ID? For istance: Equipment ID 002 hex (Flight Management Computer) would require 12 bits to be represented. Where are located these bits in the ARINC word, so that the receiver could read the it? Thanks for your assistance.
ARINC 429 is a unidirectional one-to-many (broadcast) transfer bus with a maximum of 20 receivers.
Design with four unidirectional ARINC 429 buses
There is normally little need to identify the source, as there is only one. So there is no field in the protocol word dedicated for ID transmission. As visible in the previous image, bidirectional exchanges require two buses and several ports to connect them. The receiving unit (LRU) can determine from the port used which source feeds the bus.
However label 377 (octal) can be used to transmit, from time to time, the equipment ID if desired. Example: ID 10D (hex):
Source: ARINC specifications
Note: On the other hand, SDI bits can be used by the source to select the receiver.