I am confused about Digital Radio Transmissions, Plz Guide

[moonnightingale]

Hi,
I know about AM, FM and Phase modulation and also about FSK and ASK. But i m unable to understand how these new digital Radio links Transmit in air. we have purchased Radio Link RL-432 of Erricson and they claim it that it transmitts digitally.
Can u tell what modulation technique the Radio links use. Is it normal FM or something special through which they transmit signal in air.
I m writing few lines from Manual of Radio link. Kindly explain them also.

""Transmission of digital data in multiple transmission channels.
TDM allows mode 256,512,1024 and 2048 Kbit/sec.
Modulation Type = Binary FM Modulation Index 0,7""
I also have fair idea abt TDM but what we mean by rates. And what is BINARY FM. this is new.
Can the radio link transmit in air without AM or FM?? Do tell me. Is there anywhere Digital Transmission (Modulation) taking place for transmission.
Thanks a lot.

[Tomi Engdahl]

Check the answers posted here:
http://www.epanorama.net/phpBB2/viewtopic.php?t=32210