Mandatory in a conditional sequence (C4)
This field contains the sequential number of the allocation (Entry Number), optionally followed by the sequence number of the message (Page Number) within that instruction when more than one MT 303 is sent for one instruction.
Entry Number starts with 1 for a new instruction. It is increased by one with each individual allocation even if more than one MT 303 is sent for one instruction.
If used, Page Number always starts with 1. When several messages are sent to convey information about a single entry, the first message must contain '/1' in Page Number. This number must be incremented by one for each additional message.
Both Entry Number and Page Number enable the Receiver to put the different MTs 303 into sequence and thus form the complete allocation instruction.