User Manual

Protocol support: Radio Access Protocol (RAP)

Integrator’s Guide – RIM 801D OEM Radio Modem

checksum, the three trailer bytes must be received before the frame is

accepted.

Please make sure you understand that the RAP header, type, length,

checksum, and trailer bytes are never transmitted to the wireless network.

These bytes are used only in communication between the radio modem and

the host device. Only the bytes contained in the DATA field are transmitted

to the network. When using DataTAC, the entire SDU is enclosed in the

RAP frame’s DATA field, as shown in the following diagram:

Header Type Data Checksum TrailerLength

SDU inserts into the DATA

field of RAP frame

Only the

SDU is sent over

the DataTAC wireless network

AP transmit

rame

Transmit

SDU

0xFB 0xEA 0xD90x9D 0xAE 0xBF

Data

SDU Header Data

User data

SDU

000XYZZY

XYZZY

1111111122222222x

11111111

22222222x

Figure 11: Sending data from the host to the wireless network

RAP frame types

There are eighteen RAP frame types. These frame types identify the type of

data that is being sent. The different frame types are summarized in the table

below, and discussed in greater detail in the Programmer’s Guide to RAP

and SDUs.

Please note that although the information below is specific to the DataTAC

network in its use of the term SDU, the RAP protocol is network-

independent. The term SDU can be freely replaced with data packet,the

structure of which would depend on the network in use.