Motorola M3097 Service Manual download pdf (Page 17)

©1999 Motorola, Inc.

TDMA M3090/M3097Cellular Overview

6

the complement of the assigned DSAT.

SAT (Supervisory Audio Tone) and DSAT

(Digital SAT)

The Supervisory Audio Tone (SAT) is one of

three frequencies around 6 kHz used in

AMPS signaling. On NAMPS channels SAT

is replaced by one of seven sub-audible digi-

tal equivalents or vectors called DSAT. SAT

(or DSAT) is generated by the cell site,

checked for frequency or accuracy by the cel-

lular telephone, then transponded (that is,

not merely reflected but generated and re-

turned) to the cell site on the reverse voice

channel (REVC). The cellular telephone uses

(D)SAT to verify that it is tuned to the cor-

rect channel after a new voice channel as-

signment. When the central controller

(switch) signals the mobile regarding the new

SAT 0 (5970 Hz)

SAT 1 (6000 Hz)

SAT 2 (6030 Hz)

Cellular System

Re-use

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voice channel, it also informs the mobile of

the SAT frequency or DSAT vector to expect

on the new channel. The returned (D)SAT

is used at the cell site to verify the presence

of the telephone’s signal on the designated

channel.

In general there are three uses of (D)SAT:

(a) it provides a form of squelch; (b) it pro-

vides for call continuation (but if equipped

for it, the switch will allow for VOX on all

models); and (c) (D)SAT is used to prevent

co-channel interference.

DTMF (Dual Tone Multi-Frequency)

DTMF (Dual Tone Multi-Frequency) touch-

code dialing may also occur on voice chan-

nels. DTMF selects two tones from a total of

nine (cellular only uses seven of these tones /

four low and three high tones) to uniquely

represent individual keys.

Figure 4. Channel Assignments

Table 6. DTMF Values

Analog Cellular

Key Low Tone High Tone

1 697 1209

2 697 1336

3 697 1477

4 770 1209

5 770 1336

6 770 1477

7 852 1209

8 852 1336

9 852 1477

* 941 1209

0 941 1336

# 941 1477

1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 132 133

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