User's Manual

Table Of Contents

SC14CVMDECT Cordless Voice Module

4.7 PROTOCOL STACK

The protocol stack handles the RF interface. For the

SC14CVMDECT the DECT TDMA is used. The

protocol features encryption.

4.7.1 DECT TBR22

The SC14CVMDECT protocol supports the DECT GAP

standard. DECT TBR22 GAP type approval however is

optional.

To pass a GAP type approval, a disable of the PP

authentication and encryption during conversation is

needed for some TBR22 test cases (DLC test cases).

This can be done via EEPROM address 0x00F0.

4.7.2 Out-of-Range handling

When the PP goes in-range or out-of-range a signal is

sent from the PP to the MMI Software indicating

whether the PP is in-lock or is out-of-lock with the FP.

4.7.3 Pre-amble Antenna diversity

To optimize the audio quality caused by rapid changing

radio paths (fading), the SC14CVMDECT supports

pre-amble antenna diversity. The pre-amble diversity

algorithm uses RSSI measurements to judge the radio

signal strength on both antennas and, as a result of it,

the choice of the best performing antenna is

determined. The antenna will be used for the receive

slot and the next transmit slot.

The pre-amble antenna diversity is supported by

default. The pre-amble diversity can be disabled by

EEPROM to let the SC14CVMDECT support a single

antenna. See document reference [2].

In general an FP uses diversity and a PP does not.

4.7.4 Low Speed Data

During a voice call or using a service call, data can be

transferred at a rate of about 1.6 Kbit/s using IWU to

IWU messaging.

Figure 13 Low Speed Data Scenario