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docs/amps.html
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@ -10,8 +10,6 @@
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||||||
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||||||
<center><img src="amps.jpg"/></center>
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<center><img src="amps.jpg"/></center>
|
||||||
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|
||||||
<center><h1>*this doc is under construction*</h1></center>
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||||||
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|
||||||
<ul>
|
<ul>
|
||||||
<li><a href="#history">History</a>
|
<li><a href="#history">History</a>
|
||||||
<li><a href="#howitworks">How it works</a>
|
<li><a href="#howitworks">How it works</a>
|
||||||
|
@ -65,10 +63,28 @@ 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>.
|
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.
|
Click for reading the PDF file.
|
||||||
Thanx to TIA for allowing me to add the standard document to this project's documentation.
|
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>
|
<i>Reproduced under written permission from Telecommunications Industry Association.</i>
|
||||||
</p>
|
</p>
|
||||||
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|
||||||
|
<center><img src="amps-cells.jpg"/></center>
|
||||||
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|
||||||
|
<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>
|
<p>
|
||||||
An AMPS network is divided into two systems, System A and System B.
|
An AMPS network is divided into two systems, System A and System B.
|
||||||
Both systems have different radio channels.
|
Both systems have different radio channels.
|
||||||
|
@ -93,37 +109,52 @@ A radio noise floor of 10% would be reduced to 1% by the expander.
|
||||||
</p>
|
</p>
|
||||||
|
|
||||||
<p>
|
<p>
|
||||||
Amps system was the first cellular system.
|
The signaling is done with Manchester Code.
|
||||||
By reducing cell size, the frequencies can be reused in lower distances, so more calls can be made in an area with the same amount of channels.
|
The symbol rate is 10,000 Hz, resulting in a frequency of 10 KHz.
|
||||||
Different cell sizes require a control of the tranmission power of the phone and the base station.
|
To allow such high frequencies, the carrier frequency is directly shifted, instead of modulating two alternating tones.
|
||||||
A system with small cells must handoff (handover) the call to another cell, if a subscriber moves outside the coverage area.
|
</p>
|
||||||
In order to know where a phone can be reached, it must register to a new cell (area), if it moves.
|
|
||||||
A database keeps track of the current location of the mobile phone.
|
<center><img src="amps-focc.png"/></center>
|
||||||
</p>
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|
||||||
|
<p>
|
||||||
<p>
|
As depicted, each frame that is sent on the control channel of a base station,
|
||||||
<font color="red">Registering, power control and handoff are the key features of a cellular network.</font>
|
starts with a dotting sequence (1010101...) to sync the receiver
|
||||||
</p>
|
and a sync word (11100010010) to indicate start of message.
|
||||||
|
Two words of 40 bits are repeated 5 times for redundancy.
|
||||||
<p>
|
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'.
|
||||||
</p>
|
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.
|
||||||
<p>
|
The bad news is, that the base station must react in less than 5 milliseconds, which is too fast for Osmocom-Analog.
|
||||||
</p>
|
The good news is, that this feature can be turned off.
|
||||||
|
</p>
|
||||||
<p>
|
|
||||||
</p>
|
<center><img src="amps-words.png"/></center>
|
||||||
|
|
||||||
<p>
|
<p>
|
||||||
</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.
|
||||||
<p>
|
They are used for parity check, resulting in 28 usable bit for the message itself.
|
||||||
</p>
|
Other words are used to broadcast cell info of the base station.
|
||||||
|
</p>
|
||||||
<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>
|
||||||
|
|
||||||
<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>
|
||||||
|
|
||||||
<p class="toppic">
|
<p class="toppic">
|
||||||
|
@ -166,7 +197,7 @@ The transmitter will now shift frequency according the the level of the sound ca
|
||||||
In my case, my sound card is connected to a transmitter, where a positive sample value causes a negative frequency deviation.
|
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.
|
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'.
|
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 disciminator.
|
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 '-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).
|
I use the calling channel (control channel) 334, which could also be used as traffic channel (voice channel).
|
||||||
</p>
|
</p>
|
||||||
|
@ -181,85 +212,168 @@ Selected System ID (SID) 40 belongs to:
|
||||||
San Jose, CA (GTE Mobile)
|
San Jose, CA (GTE Mobile)
|
||||||
San Rosa, CA (GTE Mobile)
|
San Rosa, CA (GTE Mobile)
|
||||||
Santa Barbara, CA (GTE Mobile)
|
Santa Barbara, CA (GTE Mobile)
|
||||||
amps.c:390 notice : You selected 'combined control & paging & voice channel'.
|
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.
|
This is a hack, but the only way to use control channel and voice channel on one transceiver.
|
||||||
Some phones may reject this.
|
Some phones may reject this, but all my phones don't.
|
||||||
amps.c:481 info : Entering IDLE state, sending Overhead/Filler frames on combined control & paging
|
amps.c:632 info : Entering IDLE state, sending Overhead/Filler frames on combined control & paging
|
||||||
& voice channel.
|
& voice channel.
|
||||||
Base station on channel 334 ready, please tune transmitter to 880.020 MHz and receiver to 835.020 MHz.
|
dsp.c:909 info : Change mode to FOCC
|
||||||
frame.c:3658 info : RX Level: 54% Quality: 66% Polarity: NEGATIVE
|
amps.c:585 notice : Created channel #334 (System B) of type 'CC/PC/VC' = combined control & paging
|
||||||
frame.c:3658 info : RX Level: 53% Quality: 65% Polarity: NEGATIVE
|
& voice channel
|
||||||
frame.c:3658 info : RX Level: 52% Quality: 60% Polarity: NEGATIVE
|
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>
|
</pre>
|
||||||
|
|
||||||
<p>
|
<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.
|
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.
|
Then tune to actually up-link frequency 835.020 MHz.
|
||||||
The actual level is not yet relevant.
|
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.)
|
(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>
|
||||||
|
|
||||||
<p>
|
<p>
|
||||||
If the polarity is correct and the volume of the signal (frequency deviation) is about right, you will make the phone register.
|
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 uplink.
|
The phone will transmit on the up-link.
|
||||||
If not, try other polarity.
|
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:
|
This is how my phone registers to my network:
|
||||||
</p>
|
</p>
|
||||||
|
|
||||||
<pre>
|
<pre>
|
||||||
|
|
||||||
frame.c:3630 info : RX RECC: DCC=0
|
frame.c:3711 info : RX Level: 93% Quality: 99% Polarity: POSITIVE
|
||||||
frame.c:2990 info : Received: Word A - Abbreviated Address Word
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
||||||
frame.c:2990 info : Received: Word B - Extended Address Word
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
||||||
frame.c:2990 info : Received: Word C - Serial Number Word
|
frame.c:3322 info : expecting 2 more word(s) to come
|
||||||
amps.c:635 info : Registration 617XXXXXXX (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
transaction.c:175 info : Transaction state IDLE -> REGISTER ACK
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
||||||
transaction.c:98 info : Created transaction '617XXXXXXX' for subscriber 'REGISTER ACK'
|
frame.c:3322 info : expecting 1 more word(s) to come
|
||||||
amps.c:989 info : Sending Register acknowledge
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
transaction.c:175 info : Transaction state REGISTER ACK -> REGISTER ACK SEND
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
frame.c:3322 info : expecting 0 more word(s) to come
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
amps.c:793 info : Registration 617XXXXXXX (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
or IS-54A mobile station)
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
amps.c:799 info : -> Home country: USA
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
amps.c:801 info : -> Home number: 617XXXXXXX
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
transaction.c:245 info : Transaction state IDLE -> REGISTER ACK
|
||||||
transaction.c:117 info : Destroying transaction for subscriber '617XXXXXXX'
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
||||||
transaction.c:175 info : Transaction state REGISTER ACK SEND -> IDLE
|
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>
|
</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>
|
<pre>
|
||||||
|
|
||||||
frame.c:3630 info : RX RECC: DCC=0
|
frame.c:3711 info : RX Level: 91% Quality: 96% Polarity: POSITIVE
|
||||||
frame.c:2990 info : Received: Word A - Abbreviated Address Word
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
||||||
frame.c:2990 info : Received: Word B - Extended Address Word
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
||||||
frame.c:2990 info : Received: Word C - Serial Number Word
|
frame.c:3322 info : expecting 3 more word(s) to come
|
||||||
frame.c:2990 info : Received: Word D - First Word of the Called-Address (Origination - Voice Service)
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
amps.c:653 info : Call 617XXXXXXX -> 5551212 (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
||||||
transaction.c:175 info : Transaction state IDLE -> CALL ASSIGN MOBILE ORIGINAT ING
|
frame.c:3322 info : expecting 2 more word(s) to come
|
||||||
transaction.c:98 info : Created transaction '617XXXXXXX' for subscriber 'CALLASSIGN MOBILE ORIGINATING'
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
amps.c:1003 info : Assigning channel to call from mobile station
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
||||||
transaction.c:175 info : Transaction state CALL ASSIGN MOBILE ORIGINATING ->
|
frame.c:3322 info : expecting 1 more word(s) to come
|
||||||
CALL ASSIGN MOBILE ORIGINATING SEND
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
frame.c:3059 info : Received: Word D - First Word of the Called-Address (Origination - Voice Service)
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
frame.c:3322 info : expecting 0 more word(s) to come
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
amps.c:816 info : Call 617XXXXXXX -> 9200 (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
or IS-54A mobile station)
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
transaction.c:245 info : Transaction state IDLE -> CALL ASSIGN MOBILE ORIGINATING
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
||||||
transaction.c:175 info : Transaction state CALL ASSIGN MOBILE ORIGINATING SEND -> CALL
|
amps.c:1156 info : Assigning channel to call from mobile station
|
||||||
amps.c:951 info : Staying on combined control + voice channel 334
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE ORIGINATING -> CALL ASSIGN MOBILE ORIGINATING SEND
|
||||||
amps.c:959 info : Setup call to network.
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
call.c:590 info : Incoming call from '617XXXXXXX' to '5551212'
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
dsp.c:678 notice : SAT level 72.31% quality 98%p)
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
dsp.c:678 notice : SAT level 78.63% quality 100%)
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
dsp.c:678 notice : SAT level 78.76% quality 100%)
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
amps.c:585 info : Detected SAT signal with quality=100.
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
dsp.c:678 notice : SAT level 78.66% quality 100%)
|
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>
|
</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>
|
<pre>
|
||||||
|
|
||||||
amps.c:525 info : Detected Signaling Tone with quality=100.
|
amps.c:525 info : Detected Signaling Tone with quality=100.
|
||||||
|
@ -271,60 +385,84 @@ amps.c:481 info : Entering IDLE state, sending Overhead/Filler frames on combi
|
||||||
|
|
||||||
</pre>
|
</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>
|
<pre>
|
||||||
|
|
||||||
call.c:457 info : Outgoing call to 617XXXXXXX
|
call.c:594 info : Outgoing call to 617XXXXXXX
|
||||||
amps.c:753 info : Call to mobile station, paging station id '617XXXXXXX'
|
amps.c:929 info : Call to mobile station, paging station id '617XXXXXXX'
|
||||||
transaction.c:175 info : Transaction state IDLE -> PAGE
|
transaction.c:245 info : Transaction state IDLE -> PAGE
|
||||||
transaction.c:98 info : Created transaction '617XXXXXXX' for subscriber 'PAGE'
|
transaction.c:150 info : Created transaction for subscriber '617XXXXXXX'
|
||||||
amps.c:1025 info : Paging the phone
|
amps.c:1184 info : Paging the phone
|
||||||
transaction.c:175 info : Transaction state PAGE -> PAGE SEND
|
transaction.c:245 info : Transaction state PAGE -> PAGE SEND
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC == 11)
|
||||||
transaction.c:175 info : Transaction state PAGE SEND -> PAGE REPLY
|
transaction.c:245 info : Transaction state PAGE SEND -> PAGE REPLY
|
||||||
frame.c:3658 info : RX Level: 60% Quality: 90% Polarity: POSITIVE
|
frame.c:3711 info : RX Level: 90% Quality: 95% Polarity: POSITIVE
|
||||||
frame.c:3630 info : RX RECC: DCC=0
|
frame.c:3680 info : RX RECC: DCC=0 (5 of 5 CRCs are ok)
|
||||||
frame.c:2990 info : Received: Word A - Abbreviated Address Word
|
frame.c:3059 info : Received: Word A - Abbreviated Address Word
|
||||||
frame.c:2990 info : Received: Word B - Extended Address Word
|
frame.c:3322 info : expecting 2 more word(s) to come
|
||||||
frame.c:2990 info : Received: Word C - Serial Number Word
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
amps.c:655 info : Paging reply 617XXXXXXX (ESN = 825b5f79, Class 6 / Discontinuous / 25 MHz)
|
frame.c:3059 info : Received: Word B - Extended Address Word
|
||||||
transaction.c:175 info : Transaction state PAGE REPLY -> CALL ASSIGN MOBILE TERMINATING
|
frame.c:3322 info : expecting 1 more word(s) to come
|
||||||
amps.c:1012 info : Assigning channel to call to mobile station
|
frame.c:3688 info : RX RECC: (5 of 5 CRCs are ok)
|
||||||
transaction.c:175 info : Transaction state CALL ASSIGN MOBILE TERMINATING ->
|
frame.c:3059 info : Received: Word C - Serial Number Word
|
||||||
CALL ASSIGN MOBILE TERMINATING SEND
|
frame.c:3322 info : expecting 0 more word(s) to come
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
amps.c:814 info : Paging reply 617XXXXXXX (ESN = 8a376086, Class 1 / Continuous / 25 MHz, TIA/EIA-553
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
or IS-54A mobile station)
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
transaction.c:245 info : Transaction state PAGE REPLY -> CALL ASSIGN MOBILE TERMINATING
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
amps.c:1168 info : Assigning channel to call to mobile station
|
||||||
frame.c:2691 info : Transmit: Word 1 - Abbreviated Address Word
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE TERMINATING -> CALL ASSIGN MOBILE TERMINATING SEND
|
||||||
frame.c:2691 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
transaction.c:175 info : Transaction state CALL ASSIGN MOBILE TERMINATING SEND ->
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
CALL ALERT MOBILE TERMINATING
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
amps.c:951 info : Staying on combined control + voice channel 334
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
frame.c:2691 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
frame.c:2739 info : Transmit: Word 1 - Abbreviated Address Word
|
||||||
dsp.c:678 notice : SAT level 76.43% quality 98%
|
frame.c:2739 info : Transmit: Word 2 - Extended Address Word (SCC != 11)
|
||||||
frame.c:2691 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
amps.c:1104 info : Staying on combined control + voice channel 334
|
||||||
dsp.c:678 notice : SAT level 77.44% quality 99%
|
amps.c:1174 info : Assignment complete, next: sending alerting on VC
|
||||||
frame.c:2691 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
transaction.c:245 info : Transaction state CALL ASSIGN MOBILE TERMINATING SEND -> CALL ALERT MOBILE TERMINATING
|
||||||
dsp.c:678 notice : SAT level 78.58% quality 99%
|
dsp.c:915 info : Change mode from FOCC to FVC
|
||||||
amps.c:585 info : Detected SAT signal with quality=99.
|
amps.c:1216 info : Sending alerting
|
||||||
frame.c:2691 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
||||||
dsp.c:678 notice : SAT level 79.75% quality 100%
|
dsp.c:762 notice : SAT level 101.24% quality 98%
|
||||||
amps.c:525 info : Detected Signaling Tone with quality=100.
|
dsp.c:762 notice : SAT level 101.47% quality 95%
|
||||||
call.c:646 info : Call is alerting
|
amps.c:1216 info : Sending alerting
|
||||||
transaction.c:175 info : Transaction state CALL ALERT MOBILE TERMINATING ->
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
||||||
CALL ALERT MOBILE TERMINATING SEND
|
dsp.c:762 notice : SAT level 98.32% quality 95%
|
||||||
dsp.c:678 notice : SAT level 67.88% quality 98%
|
dsp.c:762 notice : SAT level 95.59% quality 97%
|
||||||
dsp.c:678 notice : SAT level 80.28% quality 99%
|
amps.c:1216 info : Sending alerting
|
||||||
dsp.c:678 notice : SAT level 80.39% quality 99%
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
||||||
dsp.c:678 notice : SAT level 80.08% quality 100%
|
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>
|
</pre>
|
||||||
|
|
||||||
|
<p>
|
||||||
|
The phone sends a signaling tone while it is ringing.
|
||||||
|
If the user answers, the phone stops signaling tone.
|
||||||
|
</p>
|
||||||
|
|
||||||
<pre>
|
<pre>
|
||||||
|
|
||||||
mps.c:527 info : Lost Signaling Tone signal
|
mps.c:527 info : Lost Signaling Tone signal
|
||||||
|
@ -333,24 +471,30 @@ transaction.c:175 info : Transaction state CALL ALERT MOBILE TERMINATING SEND
|
||||||
|
|
||||||
</pre>
|
</pre>
|
||||||
|
|
||||||
|
<p>
|
||||||
|
If the base station hangs up, it sends a release message on forward voice channel (FVC).
|
||||||
|
To hangup, press 'h'.
|
||||||
|
</p>
|
||||||
|
|
||||||
<pre>
|
<pre>
|
||||||
|
|
||||||
call.c:479 info : Call hangup
|
call.c:619 info : Call hangup
|
||||||
amps.c:836 info : Call has been released by network, releasing call.
|
amps.c:999 info : Call has been released by network, releasing call.
|
||||||
amps.c:866 info : Call control releases on voice channel, releasing towards mobile station.
|
amps.c:1019 info : Call control releases on voice channel, releasing towards mobile station.
|
||||||
transaction.c:175 info : Transaction state CALL -> CALL RELEASE
|
transaction.c:245 info : Transaction state CALL -> CALL RELEASE
|
||||||
amps.c:1048 info : Releasing call to mobile station
|
amps.c:1207 info : Releasing call towards mobile station
|
||||||
transaction.c:175 info : Transaction state CALL RELEASE -> CALL RELEASE SEND
|
transaction.c:245 info : Transaction state CALL RELEASE -> CALL RELEASE SEND
|
||||||
frame.c:2691 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
frame.c:2739 info : Transmit: Mobile Station Control Message Word 1 (SCC == 11)
|
||||||
dsp.c:678 notice : SAT level 76.60% quality 100%
|
dsp.c:762 notice : SAT level 102.37% quality 96%
|
||||||
transaction.c:117 info : Destroying transaction for subscriber '617XXXXXXX'
|
dsp.c:762 notice : SAT level 101.61% quality 98%
|
||||||
transaction.c:175 info : Transaction state CALL RELEASE SEND -> IDLE
|
amps.c:1211 info : Release call was sent, destroying call
|
||||||
amps.c:481 info : Entering IDLE state, sending Overhead/Filler frames on combined control &
|
transaction.c:163 info : Destroying transaction for subscriber '617XXXXXXX'
|
||||||
paging & voice channel.
|
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>
|
</pre>
|
||||||
|
|
||||||
|
|
||||||
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
|
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
|
||||||
</td></tr></table></center>
|
</td></tr></table></center>
|
||||||
</body>
|
</body>
|
||||||
|
|
BIN
docs/amps.jpg
Before Width: | Height: | Size: 175 KiB After Width: | Height: | Size: 81 KiB |
BIN
docs/fvc.png
Before Width: | Height: | Size: 207 KiB |
BIN
docs/recc.png
Before Width: | Height: | Size: 131 KiB |
|
@ -10,23 +10,9 @@
|
||||||
|
|
||||||
<center><img src="tacs.jpg"/></center>
|
<center><img src="tacs.jpg"/></center>
|
||||||
|
|
||||||
<center><h1>*this doc is under construction*</h1></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>
|
<p>
|
||||||
*TBD*
|
Total Access Communication System (TACS) and ETACS are mostly-obsolete variants of Advanced Mobile Phone System (AMPS) which was announced as the choice for the first two UK national cellular systems in Feb 1983.
|
||||||
|
</p>
|
||||||
|
|
||||||
|
|
||||||
<ul>
|
<ul>
|
||||||
<li>Frequency range base station: 935.0125 MHz - 949.9875 MHz
|
<li>Frequency range base station: 935.0125 MHz - 949.9875 MHz
|
||||||
|
@ -43,20 +29,22 @@ History
|
||||||
<li>Mobile station transmit power: 10 or 4 Watts (vehicular) 1.6 or 0.63 Watts
|
<li>Mobile station transmit power: 10 or 4 Watts (vehicular) 1.6 or 0.63 Watts
|
||||||
<li>Base station transmit power: ??? (around 50 Watts)
|
<li>Base station transmit power: ??? (around 50 Watts)
|
||||||
</ul>
|
</ul>
|
||||||
|
|
||||||
|
<p>
|
||||||
|
TACS is the UK version of the AMPS.
|
||||||
|
There are three major differences:
|
||||||
</p>
|
</p>
|
||||||
|
|
||||||
|
<ul>
|
||||||
|
<li>Different channel frequencies
|
||||||
|
<li>6,400 Hz signaling rate (instead of 8,000 Hz)
|
||||||
|
<li>Encoding of mobile station number
|
||||||
|
</ul>
|
||||||
|
|
||||||
<p class="toppic">
|
<p>
|
||||||
<a name="howitworks"></a>
|
Refer to <a href="amps.html">AMPS</a> documentation, but use executable 'tacs' instead of 'amps'.
|
||||||
How it works
|
|
||||||
</p>
|
</p>
|
||||||
|
|
||||||
<p class="toppic">
|
|
||||||
<a name="basestation"></a>
|
|
||||||
Setup of a base station
|
|
||||||
</p>
|
|
||||||
|
|
||||||
|
|
||||||
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
|
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
|
||||||
</td></tr></table></center>
|
</td></tr></table></center>
|
||||||
</body>
|
</body>
|
||||||
|
|