User's Manual

USER MANUAL

PTM 215ZE – 2.4 GHz IEEE 802.15.4 Pushbutton Transmitter Module

3.2 Telegram Structure

PTM 215ZE transmits radio telegrams in the 2.4 GHz band according to the IEEE 802.15.4

frame structure using a ZigBee Green Power compliant payload.

Note that the byte order used by these standards is little endian. This means that for multi-

byte structures (such as 2 byte, 4 byte or 8 byte fields) the least significant byte (LSB) is

transmitted first.

The frame structure used by PTM 215ZE consists of the following four main parts:

 PHY Header

The PHY header indicates to the receiver the start of a transmission and provides infor-

mation about the length of the transmission.

It contains the following fields:

- Preamble

Pre-defined sequence (4 byte, value 0x00000000) used to adjust the receiver

to the transmission of the sender

- Start of frame

Pre-defined symbol (1 byte, value 0xA7) identifying the start of the actual data

frame

- Length of frame

1 byte indicating the combined length of all following fields

 MAC Header

The MAC header provides detailed information about the frame.

It contains the following fields:

- Frame control field

2 bytes (always 0x0801) which identify frame type, protocol version, addressing

and security mode

- Sequence number

1 byte sequential number to identify the order of transmitted frames

- Address

PAN ID and address of source (if present) and destination of the telegram

PTM 215ZE does not use source address and source PAN ID

 MAC Payload

The MAC payload is based on the ZigBee Green Power standard. It contains telegram

control, device ID, telegram data and telegram security fields.

 MAC Trailer

The MAC Trailer contains the Frame Check Sum (FCS) field used to verify the integrity of

the telegram data.