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<html>
<head>
<link href="style.css" rel="stylesheet" type="text/css" />
<title>osmocom-analog</title>
</head>
<body>
<center><table><tr><td>

<h2><center>AMPS</center></h2>

<center><img src="amps.jpg"/></center>

<ul>
	<li><a href="#history">History</a>
	<li><a href="#howitworks">How it works</a>
	<li><a href="#basestation">Setup of a base station</a>
</ul>

<p class="toppic">
<a name="history"></a>
History
</p>

<p>
*TBD*
</p>

<center><img src="amps-dynatac.jpg"/></center>

<p>
<ul>
	<li>Frequency range base station: 869.040 MHz - 893.970 MHz
	<li>Frequency range mobile station: 824.040 MHz - 848.970 MHz
	<li>Control channels: 21 for System A
	<li>Voice channels: 395 for System A (formerly 312)
	<li>Control channels: 21 for System B
	<li>Voice channels: 395 for System B (formerly 312)
	<li>Duplex distance: 45 MHz
	<li>Channel spacing: 30 KHz
	<li>Voice modulation: FM
	<li>Signaling modulation: carrier FSK
	<li>Frequency deviation: 8 KHz (FSK)
	<li>Mobile station transmit power: 4 Watts (vehicular) 1.6 or 0.6 Watts
	<li>Base station transmit power: ??? (around 50 Watts)
</ul>
</p>


<p class="toppic">
<a name="howitworks"></a>
</p>

<p>
*TBD*
</p>

<p>
*TBD* SID and System A/B
</p>

<p>
To reduce radio noise, a syllabic compandor is used on both ends.
This compresses the audio level dynamics by 2.
An audio level of 25% is raised to 50% by the compressor and lowered to 25% by the expandor.
A radio noise floor of 10% would be reduced to 1% by the expandor.
</p>

<p class="toppic">
<a name="basestation"></a>
Setup of a base station
</p>

<p>
*TBD*
</p>

<pre>

# amps -k 334 -F yes -E -e
...
Selected System ID (SID) 40 belongs to:
        Salinas, CA (GTE Mobile)
        San Francisco, CA (GTE Mobile)
        San Jose, CA (GTE Mobile)
        San Rosa, CA (GTE Mobile)
        Santa Barbara, CA (GTE Mobile)
amps.c:390 notice : You selected 'combined control &amp; paging &amp; voice channel'.
This is a hack, but the only way to use control channel and voice channel on one transceiver.
 Some phones may reject this.
amps.c:481 info   : Entering IDLE state, sending Overhead/Filler frames on combined control &amp; paging
 &amp; voice channel.
Base station on channel 334 ready, please tune transmitter to 880.020 MHz and receiver to 835.020 MHz.
frame.c:3658 info   : RX Level: 54% Quality: 66% Polarity: NEGATIVE
frame.c:3658 info   : RX Level: 53% Quality: 65% Polarity: NEGATIVE
frame.c:3658 info   : RX Level: 52% Quality: 60% Polarity: NEGATIVE

</pre>

<p>
You should tune the receiver to 880.020 first, to check if you can hear and decode the idle signal from the base station.
Then tune to actually uplink frequency 835.020 MHz.
The actual level is not yet relevant.
(You may check the quality using '-L 2' command line option and build a radio loop by tuning the receiver to the transmitter.)
</p>

<pre>

frame.c:3630 info   : RX RECC: DCC=0
frame.c:2990 info   : Received: Word A - Abbreviated Address Word
frame.c:2990 info   : Received: Word B - Extended Address Word
frame.c:2990 info   : Received: Word C - Serial Number Word
amps.c:635 info   : Registration 617XXXXXXX (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
transaction.c:175 info   : Transaction state IDLE -&gt; REGISTER ACK
transaction.c:98 info   : Created transaction '617XXXXXXX' for subscriber 'REGISTER ACK'
amps.c:989 info   : Sending Register acknowledge
transaction.c:175 info   : Transaction state REGISTER ACK -&gt; REGISTER ACK SEND
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
transaction.c:117 info   : Destroying transaction for subscriber '617XXXXXXX'
transaction.c:175 info   : Transaction state REGISTER ACK SEND -&gt; IDLE

</pre>

<pre>

frame.c:3630 info   : RX RECC: DCC=0
frame.c:2990 info   : Received: Word A - Abbreviated Address Word
frame.c:2990 info   : Received: Word B - Extended Address Word
frame.c:2990 info   : Received: Word C - Serial Number Word
frame.c:2990 info   : Received: Word D - First Word of the Called-Address (Origination - Voice Service)
amps.c:653 info   : Call 617XXXXXXX -&gt; 5551212 (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
transaction.c:175 info   : Transaction state IDLE -&gt; CALL ASSIGN MOBILE ORIGINAT ING
transaction.c:98 info   : Created transaction '617XXXXXXX' for subscriber 'CALLASSIGN MOBILE ORIGINATING'
amps.c:1003 info   : Assigning channel to call from mobile station
transaction.c:175 info   : Transaction state CALL ASSIGN MOBILE ORIGINATING -&gt;
CALL ASSIGN MOBILE ORIGINATING SEND
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
transaction.c:175 info   : Transaction state CALL ASSIGN MOBILE ORIGINATING SEND -&gt; CALL
amps.c:951 info   : Staying on combined control + voice channel 334
amps.c:959 info   : Setup call to network.
call.c:590 info   : Incoming call from '617XXXXXXX' to '5551212'
dsp.c:678 notice : SAT level 72.31% quality 98%p)
dsp.c:678 notice : SAT level 78.63% quality 100%)
dsp.c:678 notice : SAT level 78.76% quality 100%)
amps.c:585 info   : Detected SAT signal with quality=100.
dsp.c:678 notice : SAT level 78.66% quality 100%)

</pre>

<pre>

amps.c:525 info   : Detected Signaling Tone with quality=100.
transaction.c:117 info   : Destroying transaction for subscriber '617XXXXXXX'
transaction.c:175 info   : Transaction state CALL -&gt; IDLE
call.c:711 info   : Call has been released with cause=16
amps.c:481 info   : Entering IDLE state, sending Overhead/Filler frames on combined control &amp; paging
&amp; voice channel.

</pre>

<pre>

call.c:457 info   : Outgoing call to 617XXXXXXX
amps.c:753 info   : Call to mobile station, paging station id '617XXXXXXX'
transaction.c:175 info   : Transaction state IDLE -&gt; PAGE
transaction.c:98 info   : Created transaction '617XXXXXXX' for subscriber 'PAGE'
amps.c:1025 info   : Paging the phone
transaction.c:175 info   : Transaction state PAGE -&gt; PAGE SEND
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC == 11)
transaction.c:175 info   : Transaction state PAGE SEND -&gt; PAGE REPLY
frame.c:3658 info   : RX Level: 60% Quality: 90% Polarity: POSITIVE
frame.c:3630 info   : RX RECC: DCC=0
frame.c:2990 info   : Received: Word A - Abbreviated Address Word
frame.c:2990 info   : Received: Word B - Extended Address Word
frame.c:2990 info   : Received: Word C - Serial Number Word
amps.c:655 info   : Paging reply 617XXXXXXX (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
transaction.c:175 info   : Transaction state PAGE REPLY -&gt; CALL ASSIGN MOBILE TERMINATING
amps.c:1012 info   : Assigning channel to call to mobile station
transaction.c:175 info   : Transaction state CALL ASSIGN MOBILE TERMINATING -&gt;
CALL ASSIGN MOBILE TERMINATING SEND
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
frame.c:2691 info   : Transmit: Word 1 - Abbreviated Address Word
frame.c:2691 info   : Transmit: Word 2 - Extended Address Word (SCC != 11)
transaction.c:175 info   : Transaction state CALL ASSIGN MOBILE TERMINATING SEND -&gt;
CALL ALERT MOBILE TERMINATING
amps.c:951 info   : Staying on combined control + voice channel 334
frame.c:2691 info   : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
dsp.c:678 notice : SAT level 76.43% quality 98%
frame.c:2691 info   : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
dsp.c:678 notice : SAT level 77.44% quality 99%
frame.c:2691 info   : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
dsp.c:678 notice : SAT level 78.58% quality 99%
amps.c:585 info   : Detected SAT signal with quality=99.
frame.c:2691 info   : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
dsp.c:678 notice : SAT level 79.75% quality 100%
amps.c:525 info   : Detected Signaling Tone with quality=100.
call.c:646 info   : Call is alerting
transaction.c:175 info   : Transaction state CALL ALERT MOBILE TERMINATING -&gt;
CALL ALERT MOBILE TERMINATING SEND
dsp.c:678 notice : SAT level 67.88% quality 98%
dsp.c:678 notice : SAT level 80.28% quality 99%
dsp.c:678 notice : SAT level 80.39% quality 99%
dsp.c:678 notice : SAT level 80.08% quality 100%

</pre>

<pre>

mps.c:527 info   : Lost Signaling Tone signal
call.c:689 info   : Call has been answered by '617XXXXXXX'
transaction.c:175 info   : Transaction state CALL ALERT MOBILE TERMINATING SEND -&gt; CALL

</pre>

<pre>

call.c:479 info   : Call hangup
amps.c:836 info   : Call has been released by network, releasing call.
amps.c:866 info   : Call control releases on voice channel, releasing towards mobile station.
transaction.c:175 info   : Transaction state CALL -&gt; CALL RELEASE
amps.c:1048 info   : Releasing call to mobile station
transaction.c:175 info   : Transaction state CALL RELEASE -&gt; CALL RELEASE SEND
frame.c:2691 info   : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
dsp.c:678 notice : SAT level 76.60% quality 100%
transaction.c:117 info   : Destroying transaction for subscriber '617XXXXXXX'
transaction.c:175 info   : Transaction state CALL RELEASE SEND -&gt; IDLE
amps.c:481 info   : Entering IDLE state, sending Overhead/Filler frames on combined control &amp;
paging &amp; voice channel.

</pre>


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