502 lines
23 KiB
HTML
502 lines
23 KiB
HTML
<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>
|
|
The Advanced Mobile Phone Service (AMPS) was an analog cellular mobile phone system developed by Bell Labs.
|
|
From 1968 to 1983 the Bell Labs worked out the system, while Motorola was developing the cellular phone.
|
|
Dr. Martin Cooper produced the first handheld phone "DynaTAC8000x", the famous Brick Phone.
|
|
</p>
|
|
|
|
<center><img src="amps-dynatac.jpg"/></center>
|
|
<center><a href="https://en.wikipedia.org/wiki/Motorola_DynaTAC">Image taken from Wikipedia</a></center>
|
|
|
|
<p>
|
|
AMPS was one of the first modern cellular phone systems, which remained in operation until 2008.
|
|
Service started in Chicago on October 13, 1983 and in the Washington, DC area December 1983.
|
|
After divestiture, AMPS was divided among the 7 newly created Regional Holding Companies, now known as RBOCs.
|
|
</p>
|
|
|
|
<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>
|
|
How it works
|
|
</p>
|
|
|
|
<p>
|
|
The detailed communication between base station and mobile station is described in <a href="TIA_EIA_553_A.compressed.pdf">TIA/EIA-553 standard</a>.
|
|
Click for reading the PDF file.
|
|
Thanks to TIA for allowing me to add the standard document to this project's documentation.
|
|
<i>Reproduced under written permission from Telecommunications Industry Association.</i>
|
|
</p>
|
|
|
|
<center><img src="amps-cells.jpg"/></center>
|
|
|
|
<p>
|
|
The idea a cellular network was to use clusters to re-use frequencies more ofter, so more calls can be made in one area.
|
|
As depicted, in a cluster with 7 cells (A to G), all cells must use different frequencies.
|
|
All frequencies can be re-used in surrounding clusters.
|
|
In the example, the G cell can use channel 4, 5 and 6 again in all other clusters, because their distance is far enough.
|
|
As depicted, the distance is 4.6 times the radius of a cell coverage.
|
|
To increase the number of calls using the same number of channels, the size of the cells have to be reduced.
|
|
Because cells getting smaller, hand-off is required when moving from one cell area to another.
|
|
A phone in a smaller cell must transmit with lower power than in large cells.
|
|
To keep track in which cell the phone currently located, a registration process tells the mobile switching office (MSO) where the phone can be reached in case of an incoming call.
|
|
</p>
|
|
|
|
<p>
|
|
<font color="red">Registering, power control and handoff are the key features of a cellular network.</font>
|
|
</p>
|
|
|
|
<p>
|
|
An AMPS network is divided into two systems, System A and System B.
|
|
Both systems have different radio channels.
|
|
System A was assigned to carriers that own no fixed network. (non-wireline)
|
|
System B was assigned to carriers that are phone companies with a fixed network. (wireline)
|
|
</p>
|
|
|
|
<p>
|
|
Each system has a system ID (SID).
|
|
A SID defines the home network.
|
|
If it does not match with the phone's SID, the phone will show 'ROAM', if not disabled.
|
|
If the SID is odd (1, 3, 5, ...), it belongs to System A.
|
|
If the SID is even (2, 4, 6, ...), it belongs to System B.
|
|
The System A or B or both can be selected on the phone.
|
|
</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 expander.
|
|
A radio noise floor of 10% would be reduced to 1% by the expander.
|
|
</p>
|
|
|
|
<p>
|
|
The signaling is done with Manchester Code.
|
|
The symbol rate is 10,000 Hz, resulting in a frequency of 10 KHz.
|
|
To allow such high frequencies, the carrier frequency is directly shifted, instead of modulating two alternating tones.
|
|
</p>
|
|
|
|
<center><img src="amps-focc.png"/></center>
|
|
|
|
<p>
|
|
As depicted, each frame that is sent on the control channel of a base station,
|
|
starts with a dotting sequence (1010101...) to sync the receiver
|
|
and a sync word (11100010010) to indicate start of message.
|
|
Two words of 40 bits are repeated 5 times for redundancy.
|
|
An A-word belongs to mobiles with the last significant bit of their mobile identification number equals '1' and a B-word to mobiles with the last significant bit of their mobile identification number equals '0'.
|
|
Around sync and dotting and after every 10 bits of a message a B/I-bit is inserted, to indicate if the control channel is busy or not.
|
|
During an incoming message from a mobile phone, the base station will block the channels by setting the B/I-bit, so other mobile phone must wait until the channel is marked free again.
|
|
The bad news is, that the base station must react in less than 5 milliseconds, which is too fast for Osmocom-Analog.
|
|
The good news is, that this feature can be turned off.
|
|
</p>
|
|
|
|
<center><img src="amps-words.png"/></center>
|
|
|
|
<p>
|
|
This example shows two words that are used to call a mobile phone.
|
|
Each word consists of different bits, except for the last 12 bits.
|
|
They are used for parity check, resulting in 28 usable bit for the message itself.
|
|
Other words are used to broadcast cell info of the base station.
|
|
</p>
|
|
|
|
<center><img src="amps-recc.png"/></center>
|
|
|
|
<p>
|
|
The other direction is similar, but the size of the messages are different.
|
|
After dotting sequence and sync word, a digital color code (DCC) is used to prevent cells in surrounding clusters to receive the message from the mobile phone.
|
|
The size of each word is 48 bits.
|
|
These include the 36-bits-message and the 12 parity bits.
|
|
</p>
|
|
|
|
<center><img src="amps-fvc.png"/></center>
|
|
|
|
<p>
|
|
On a voice channel, the messages have even more redundancy, by repeating them 11 times.
|
|
</p>
|
|
|
|
<p>
|
|
Describing all messages with their function and their content is beyond the scope of this introduction.
|
|
Refer to the TIA specification, described above.
|
|
</p>
|
|
|
|
<p class="toppic">
|
|
<a name="basestation"></a>
|
|
Setup of a base station
|
|
</p>
|
|
|
|
<p>
|
|
<font color="red">Importaint: We need to connect to PLL and discriminator!</font>
|
|
</p>
|
|
|
|
<p>
|
|
AMPS does not use a modulated tone to carry bits of information, instead it modulates the radio carrier directly.
|
|
This image shows a signal generated by this software, which is similar to a received signal from the phone:
|
|
</p>
|
|
|
|
<center><img src="amps-burst.png"/></center>
|
|
|
|
<p>
|
|
Generally a receiver will do de-emphasis and filtering after demodulating the signal.
|
|
We don't want that.
|
|
It may work, but be sure to use a receiver with discriminator output.
|
|
This output gives direct signal of the frequency deviation of the received signal.
|
|
The signal on the sound card represents the frequency shift of the received signal.
|
|
Many receivers can be modified, so search the Web for more info.
|
|
</p>
|
|
|
|
<p>
|
|
On the transmitter we don't want to have filtering and pre-emphasis.
|
|
It may work, but be sure to use a transmitter that allows to disable emphasis.
|
|
I took the schematics of my transmitter and connected the sound card directly to the PLL.
|
|
The transmitter will now shift frequency according the the level of the sound card.
|
|
</p>
|
|
|
|
<p>
|
|
<font color="red">Importaint: We need to transmit correct polarity!</font>
|
|
</p>
|
|
|
|
<p>
|
|
In my case, my sound card is connected to a transmitter, where a positive sample value causes a negative frequency deviation.
|
|
This is why I need to flip the polarity of the signal, so I generate a negative sample value that causes a positive frequency deviation.
|
|
I use the '-F yes' option or '--flip-polarity yes'.
|
|
Also it is essential to use a transmitter with direct access to the modulator and and a receiver with direct access to the discriiminator.
|
|
I use '-p -d' or '--pre-emphasis --de-emphasis' to process emphasis for audio signal in software.
|
|
I use the calling channel (control channel) 334, which could also be used as traffic channel (voice channel).
|
|
</p>
|
|
|
|
<pre>
|
|
|
|
# amps -k 334 -F yes -p -d
|
|
...
|
|
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:531 notice : You selected 'combined control & paging & 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, but all my phones don't.
|
|
amps.c:632 info : Entering IDLE state, sending Overhead/Filler frames on combined control & paging
|
|
& voice channel.
|
|
dsp.c:909 info : Change mode to FOCC
|
|
amps.c:585 notice : Created channel #334 (System B) of type 'CC/PC/VC' = combined control & paging
|
|
& voice channel
|
|
Base station on channel 334 ready (combined control & paging & voice channel),
|
|
please tune transmitter to 880.020 MHz and receiver to 835.020 MHz.
|
|
|
|
</pre>
|
|
|
|
<pre>
|
|
|
|
# tacs -k 323 -F yes -p -d
|
|
...
|
|
Selected Area ID (AID) 3600 belongs to:
|
|
CellNet, United Kingdom
|
|
amps.c:531 notice : You selected 'combined control & paging & 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, but all my phones don't.
|
|
amps.c:632 info : Entering IDLE state, sending Overhead/Filler frames on combined control & paging
|
|
& voice channel.
|
|
dsp.c:909 info : Change mode to FOCC
|
|
amps.c:585 notice : Created channel #323 (System B) of type 'CC/PC/VC' = combined control & paging
|
|
& voice channel
|
|
Base station on channel 323 ready (combined control & paging & voice channel),
|
|
please tune transmitter to 943.0625 MHz and receiver to 898.0625 MHz.
|
|
|
|
</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 up-link frequency 835.020 MHz.
|
|
The actual level is not yet relevant.
|
|
(You may check the quality using '-l 2' or '--loopback 2' command line option and build a radio loop by tuning the receiver to the transmitter.)
|
|
</p>
|
|
|
|
<p>
|
|
If the polarity is correct and the volume of the signal (frequency deviation) is about right, you will make the phone register.
|
|
The phone will transmit on the up-link.
|
|
If not, try other polarity.
|
|
Also check if the phone allows to register on the selected system (A or B) and allowed to roam (any SID/AID).
|
|
This is how my phone registers to my network:
|
|
</p>
|
|
|
|
<pre>
|
|
|
|
frame.c:3711 info : RX Level: 93% Quality: 99% Polarity: POSITIVE
|
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
|
frame.c:3322 info : expecting 2 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
|
frame.c:3322 info : expecting 1 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
|
frame.c:3322 info : expecting 0 more word(s) to come
|
|
amps.c:793 info : Registration 617XXXXXXX (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
|
or IS-54A mobile station)
|
|
amps.c:799 info : -> Home country: USA
|
|
amps.c:801 info : -> Home number: 617XXXXXXX
|
|
transaction.c:245 info : Transaction state IDLE -> REGISTER ACK
|
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
|
amps.c:1142 info : Sending Register acknowledge
|
|
transaction.c:245 info : Transaction state REGISTER ACK -> REGISTER ACK SEND
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
transaction.c:163 info : Destroying transaction for subscriber '617XXXXXXX'
|
|
transaction.c:245 info : Transaction state REGISTER ACK SEND -> IDLE
|
|
|
|
|
|
</pre>
|
|
|
|
<p>
|
|
After some time (several minutes), the phone re-registers, because a counter in the broadcast message is incremented.
|
|
This allows the mobile switching office (MSO) to check if the phone is still available.
|
|
Changing the SID will cause the phone to register instantaneously.
|
|
</p>
|
|
|
|
<p>
|
|
Level adjustment:
|
|
We see a receive level of around 93%.
|
|
This is already good, since I did the adjustment previously.
|
|
Tune your receiver to the up-link frequency, so you get loop-back of base station broadcast.
|
|
Run the software with "-l 2" option, so it will decode its own broadcast, if looped back through radios.
|
|
Use the variable resistor (connecting your transmitter) to adjust the volume until the received level matches the same level of your previously received message.
|
|
In my case I adjust the transmitter to match around 93%. (+- 10% is good)
|
|
Now, whatever frequency deviation the phone transmits for signaling, so does your transmitter.
|
|
Use the other variable resistor (connecting your receiver) to adjust the volume until the level matches about 100%. (+- 10% is good)
|
|
Switch back the receiver to up-link frequency and restart the phone.
|
|
</p>
|
|
|
|
<p>
|
|
To make a call from the mobile phone to the base station, just enter some digits at the mobile phone and press the dial button.
|
|
The phone requests an outgoing call on the reverse control channel (RECC), including identity and called number.
|
|
The base station will send an assignment to the mobile station on forward control channel (FOCC).
|
|
Then phone an base station switch to the voice channel.
|
|
In this case we have only defined one channel, so the control channel becomes a voice channel for the duration of the call.
|
|
All other phones will loose coverage during the call.
|
|
</p>
|
|
|
|
<pre>
|
|
|
|
frame.c:3711 info : RX Level: 91% Quality: 96% Polarity: POSITIVE
|
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
|
frame.c:3322 info : expecting 3 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
|
frame.c:3322 info : expecting 2 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
|
frame.c:3322 info : expecting 1 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word D - First Word of the Called-Address (Origination - Voice Service)
|
|
frame.c:3322 info : expecting 0 more word(s) to come
|
|
amps.c:816 info : Call 617XXXXXXX -> 9200 (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
|
or IS-54A mobile station)
|
|
transaction.c:245 info : Transaction state IDLE -> CALL ASSIGN MOBILE ORIGINATING
|
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
|
amps.c:1156 info : Assigning channel to call from mobile station
|
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE ORIGINATING -> CALL ASSIGN MOBILE ORIGINATING SEND
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
amps.c:1104 info : Staying on combined control + voice channel 334
|
|
amps.c:1109 info : Setup call to network.
|
|
call.c:765 info : Incoming call from '617XXXXXXX' to '9200'
|
|
call.c:790 info : Sending MNCC call towards Network
|
|
amps.c:1162 info : Assignment complete, voice connected
|
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE ORIGINATING SEND -> CALL
|
|
dsp.c:915 info : Change mode from FOCC to FVC
|
|
dsp.c:762 notice : SAT level 101.56% quality 96%
|
|
dsp.c:762 notice : SAT level 100.97% quality 97%
|
|
dsp.c:762 notice : SAT level 102.29% quality 96%
|
|
dsp.c:762 notice : SAT level 102.31% quality 96%
|
|
dsp.c:762 notice : SAT level 102.00% quality 96%
|
|
amps.c:739 info : Detected SAT signal with quality=96.
|
|
dsp.c:762 notice : SAT level 102.04% quality 96%
|
|
dsp.c:762 notice : SAT level 102.26% quality 96%
|
|
|
|
</pre>
|
|
|
|
<p>
|
|
The SAT shows us that the level of the voice channel is right.
|
|
If a second transceiver for voice channel is used, adjust receiver to receive sat 100% (+- 10).
|
|
Then switch the receiver to the transmitter frequency and adjust transmitted SAT level to 100% (+-10.
|
|
</p>
|
|
|
|
<p>
|
|
If the mobile station hangs up, the phone transmits a signaling tone of 10 KHz:
|
|
</p>
|
|
|
|
<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 -> 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 & paging
|
|
& voice channel.
|
|
|
|
</pre>
|
|
|
|
<p>
|
|
The make a call to the phone, enter the number and press 'd' to dial.
|
|
The base station will page the mobile phone on forward control channel (FOCC).
|
|
The mobile phone will identify itself on the reverse control channel (RECC).
|
|
The base station will send an assignment to the mobile station on forward control channel.
|
|
Then phone an base station switch to the voice channel.
|
|
The base station sends rinign order message on the forward voice channel (FVC) to make the phone ring.
|
|
The mobile station will send signaling tone on reverse voice channel (RVC) to indicate that it has not been answered yet.
|
|
</p>
|
|
|
|
<pre>
|
|
|
|
call.c:594 info : Outgoing call to 617XXXXXXX
|
|
amps.c:929 info : Call to mobile station, paging station id '617XXXXXXX'
|
|
transaction.c:245 info : Transaction state IDLE -> PAGE
|
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
|
amps.c:1184 info : Paging the phone
|
|
transaction.c:245 info : Transaction state PAGE -> PAGE SEND
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
|
transaction.c:245 info : Transaction state PAGE SEND -> PAGE REPLY
|
|
frame.c:3711 info : RX Level: 90% Quality: 95% Polarity: POSITIVE
|
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
|
frame.c:3322 info : expecting 2 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
|
frame.c:3322 info : expecting 1 more word(s) to come
|
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
|
frame.c:3322 info : expecting 0 more word(s) to come
|
|
amps.c:814 info : Paging reply 617XXXXXXX (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
|
or IS-54A mobile station)
|
|
transaction.c:245 info : Transaction state PAGE REPLY -> CALL ASSIGN MOBILE TERMINATING
|
|
amps.c:1168 info : Assigning channel to call to mobile station
|
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE TERMINATING -> CALL ASSIGN MOBILE TERMINATING SEND
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
|
amps.c:1104 info : Staying on combined control + voice channel 334
|
|
amps.c:1174 info : Assignment complete, next: sending alerting on VC
|
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE TERMINATING SEND -> CALL ALERT MOBILE TERMINATING
|
|
dsp.c:915 info : Change mode from FOCC to FVC
|
|
amps.c:1216 info : Sending alerting
|
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
|
dsp.c:762 notice : SAT level 101.24% quality 98%
|
|
dsp.c:762 notice : SAT level 101.47% quality 95%
|
|
amps.c:1216 info : Sending alerting
|
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
|
dsp.c:762 notice : SAT level 98.32% quality 95%
|
|
dsp.c:762 notice : SAT level 95.59% quality 97%
|
|
amps.c:1216 info : Sending alerting
|
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
|
dsp.c:762 notice : SAT level 96.94% quality 98%
|
|
amps.c:739 info : Detected SAT signal with quality=98.
|
|
dsp.c:762 notice : SAT level 95.97% quality 97%
|
|
amps.c:1216 info : Sending alerting
|
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
|
dsp.c:762 notice : SAT level 96.28% quality 95%
|
|
dsp.c:762 notice : SAT level 95.89% quality 95%
|
|
amps.c:679 info : Detected Signaling Tone with quality=99.
|
|
call.c:830 info : Call is alerting
|
|
transaction.c:245 info : Transaction state CALL ALERT MOBILE TERMINATING -> CALL ALERT MOBILE TERMINATING SEND
|
|
|
|
</pre>
|
|
|
|
<p>
|
|
The phone sends a signaling tone while it is ringing.
|
|
If the user answers, the phone stops signaling tone.
|
|
</p>
|
|
|
|
<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 -> CALL
|
|
|
|
</pre>
|
|
|
|
<p>
|
|
If the base station hangs up, it sends a release message on forward voice channel (FVC).
|
|
To hangup, press 'h'.
|
|
</p>
|
|
|
|
<pre>
|
|
|
|
call.c:619 info : Call hangup
|
|
amps.c:999 info : Call has been released by network, releasing call.
|
|
amps.c:1019 info : Call control releases on voice channel, releasing towards mobile station.
|
|
transaction.c:245 info : Transaction state CALL -> CALL RELEASE
|
|
amps.c:1207 info : Releasing call towards mobile station
|
|
transaction.c:245 info : Transaction state CALL RELEASE -> CALL RELEASE SEND
|
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
|
dsp.c:762 notice : SAT level 102.37% quality 96%
|
|
dsp.c:762 notice : SAT level 101.61% quality 98%
|
|
amps.c:1211 info : Release call was sent, destroying call
|
|
transaction.c:163 info : Destroying transaction for subscriber '617XXXXXXX'
|
|
transaction.c:245 info : Transaction state CALL RELEASE SEND -> IDLE
|
|
amps.c:632 info : Entering IDLE state, sending Overhead/Filler frames on combined control & paging & voice channel.
|
|
dsp.c:909 info : Change mode to FOCC
|
|
|
|
</pre>
|
|
|
|
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
|
|
</td></tr></table></center>
|
|
</body>
|
|
</html>
|