FreeCalypso > hg > gsm-net-reveng

annotate tmo/CSD-tests @ 70:47947e25f922

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
tmo/CSD-tests: document experimental findings
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 25 Nov 2024 07:22:43 +0000
parents
children ed314cc25b8d
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
70
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 A series of experiments seeking to test CSD on the extant network of T-Mobile
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 USA, to be performed while this network is still alive. The main objective is
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 to test CSD calls between a single MS and analog (or PCMU-speaking) PSTN, rather
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 than mobile to mobile.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 Test setup
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 ==========
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 The test MS is an FCDEV3B with a legacy T-Mobile SIM. The AT command session
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 will be driven through the dedicated UART, not the usual fc-shell, to enable
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 full use of data functions. Rvinterf will still be used to capture logs; the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 following command needs to be issued in order to make the firmware emit traces
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 indicating AT command activity:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 sp MMI TRACECLASS 800050
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 Issue these two additional commands to trace the MMCM SAP between CC and MM
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 entities of the protocol stack:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 sp MM DUPLICATE CC PCO
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 sp CC DUPLICATE MM PCO
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 The objective is to capture all CC protocol messages sent to and received from
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 the network; tracing the exchange between CC and MM seems like the easiest way
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 to accomplish this goal within our existing firmware architecture.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 Experiment 1
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28 ============
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 In this experiment several MO CSD calls were made from the test MS to
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 +13034944774, the number for USA taxpayer-funded NIST ACTS. Several modes were
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 tested:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 AT+CBST=7,0,1 -- TI GSM MS firmware default
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 AT+CBST=7,0,0
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 AT+CBST=6,0,0
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 AT+CBST=4,0,0
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38 AT+CBST=2,0,0
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 Results were surprising:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 * Transparent mode works beautifully at 9600 baud, as well as 4800 and 1200
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43 baud. Therefore, the previous hypothesis that CSD at 9600 baud no longer
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 works as a result of GSM quality degradation or as a result of IP-fication of
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 internal transports within USA PSTN is now disproven.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 * Transparent mode at 2400 baud produced a different result: successful CONNECT
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 followed by garbage and earlier disconnect, instead of 40 s of good ACTS
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 output in other baud modes. Perhaps a defect in V.22bis implementation in
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 the network IWF?
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52 * All 3 data TCH modes were observed in L1 traces: TCH/F9.6, TCH/F4.8 and
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53 TCH/F2.4, and each of these produced a perfectly good data call in at least
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 one mode.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56 * NT mode was only tested with AT+CBST=7,0,1 default, i.e., 9600 baud and asking
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57 the IWF for V.32 modem. As revealed by L1 and CC traces, the network does
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58 everything it should - but the MS returns NO CARRIER. However, further
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 analysis of CC traces reveals that the DISCONNECT at CC level is initiated by
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 the MS and not by the network! My current working hypothesis is that the MS
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61 is unhappy about something it sees at RLP level.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 Additional observations:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 * The MS issues a single SETUP message with BC indicating ITC of 3.1 kHz and the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 selected CSD mode. The network responds with CALL PROCEEDING, ALERTING and
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67 CONNECT in the same cadence as it would for a MO voice call. The timing of
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68 ALERTING message is consistent with my expectation of when PSTN plays the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
69 ringing tone, and the timing of CC CONNECT message is consistent with my
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
70 expectation of when Answer Supervision occurs at PSTN level. The CC CONNECT
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
71 step is reached in all tested modes, including the failing NT mode.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
72
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
73 * The AT-command CONNECT response happens significantly later than CC CONNECT
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
74 message. My current working hypothesis is that the network generates CC
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
75 CONNECT when it gets Answer Supervision from PSTN just like it does for voice
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
76 calls, well before modem connection sequence can happen. Perhaps the status
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
77 of modem connection is then indicated via V.110 in-band flags, and perhaps
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
78 the MS is using that in-band status to decide when to declare CONNECT.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
79
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
80 * At the end of each call there was a network-initiated DISCONNECT with cause
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
81 value 127 (interworking, unspecified) - but in this experiment there is
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
82 insufficient information to tell if this action is initiated by the IWF upon
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
83 loss of modem signal, or if it is merely passing along PSTN-level disconnect
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
84 signaling from the called party. See Experiment 2.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
85
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
86 Experiment 2
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
87 ============
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
88
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
89 In this experiment several MO CSD call attempts were dialed from the test MS to
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
90 Mother Mychaela's personal voice number on ThemWi; the latter is interconnected
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
91 with USA PSTN via BulkVS. The objectives were: (1) to confirm the hypothesis
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
92 about Answer Supervision on PSTN side being the criterion for signaling CC
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
93 CONNECT to the MS, and (2) to hear what, if anything, the IWF transmits toward
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
94 PSTN while waiting for modem connection.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
95
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
96 Results:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
97
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
98 * When I answered the call on the destination phone, I heard silence each time.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
99 The calling party received CC CONNECT signaling when I made that answer.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
100
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
101 * In both tests where +CBST was set to 7,0,0 and I answered the call, the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
102 network (TMO) eventually ended the call, signaling cause 127 to the calling
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
103 MS like in Experiment 1. (Thus we now know that it is the IWF taking this
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
104 action, and not the called party hanging up at PSTN level.) In one of these
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
105 two tests, there was a miraculous CONNECT response from the AT interpreter,
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
106 some time well after Answer Supervision, but before the IWF-initiated
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
107 disconnect. In the second test, there was no CONNECT response, only
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
108 NO CARRIER at the time of IWF-initiated disconnect.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
109
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
110 * In the test case where I didn't answer the destination phone (let the ringing
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
111 time out), the calling MS received CC DISCONNECT message with cause 17 (user
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
112 busy), as that is how PSTN middleboxes misinterpret SIP 480 error I return
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
113 from ThemWi. The AT command interface generated BUSY response.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
114
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
115 * In the final test case in this experiment series, I made the test call with
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
116 +CBST=7,0,1 and answered the destination phone. The MS initiated DISCONNECT
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
117 4 s after receiving CC CONNECT, just like it did when calling NIST ACTS.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
118
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
119 Experiment 3
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
120 ============
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
121
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
122 This experiment sought to observe how TMO GSM network handles MT calls from PSTN
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
123 to a mobile subscriber, including the possiblity of MT CSD calls via AT+CSNS.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
124 An MT call was repeatedly dialed from Mother Mychaela's ThemWi phone to the test
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
125 MS on TMO, with different AT+CSNS and AT+CBST settings established before each
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
126 call attempt; logs were collected for subsequent analysis.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
127
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
128 Observations:
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
129
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
130 * The initial SETUP message from the network to the MS contains _no_ bearer
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
131 capability IE; the CALL CONFIRM response from the MS does include BC IE,
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
132 filled with different content depending on AT+CSNS and AT+CBST settings.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
133
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
134 * The network seems to always accept the BC supplied by the MS in that response,
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
135 and assigns appropriate TCH type and mode.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
136
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
137 * The PSTN caller hears the standard North American ringing tone while the MS
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
138 emits RING messages on its AT command channel, subsequent to the MS sending
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
139 CC ALERTING message to the network.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
140
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
141 * When I answer the call with ATA, the MS sends CC CONNECT to the network, the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
142 PSTN caller gets Answer Supervision, and I hear modem answer tones from TMO's
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
143 IWF.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
144
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
145 * Only Transparent modes have been tested so far; the modem answer sequence
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
146 heard by the PSTN caller depends on the specific modem emulation selected
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
147 with AT+CBST. With AT+CBST=2,0,0 and AT+CBST=4,0,0 I heard a continuous (no
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
148 phase reversals) V.25 ANS tone followed by a higher-pitched tone (presumably
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
149 Unscramled Binary 1s signal of V.22), followed by disconnection; with
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
150 AT+CBST=6,0,0 and AT+CBST=7,0,0 I heard a V.25 ANS tone *with* phase
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
151 reversals, directly followed by disconnection (no AC tones).
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
152
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
153 Further tests were aborted (I didn't get to testing NT mode) because the network
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
154 did something that caused the MS firmware (or perhaps the SIM) to go into a
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
155 funky state; to be investigated as its own separate problem.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
156
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
157 Experiment 4
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
158 ============
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
159
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
160 In this experiment I used two of my legacy T-Mobile SIMs simulateneously: one
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
161 in the FCDEV3B as in the preceding experiments, the other in a Pirelli DP-L10
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
162 phone. The Pirelli phone ran RAM-based FC Tourmaline firmware during these
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
163 tests. Test calls were dialed from the FCDEV3B to the Pirelli; the fw build
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
164 running on the latter has CSD excluded, but the objective was to see the MT
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
165 SETUP message as it arrives from the network, before destination MS firmware
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
166 does anything with it.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
167
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
168 Observation: _no_ BC IE was ever seen in the MT SETUP message, for both voice
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
169 and data calls dialed from the other TMO subscriber line. It appears that all
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
170 MO CSD calls were treated by the network in "convert to modem emulation" mode
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
171 despite the dialed number being another T-Mobile line; the MT leg always
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
172 received incoming voice calls.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
173
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
174 It thus appears that a change has happened in TMO's network in this regard.
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
175 Many years ago, before I learned about T vs NT distinction and other critical
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
176 CSD parameters set with AT+CBST, when I would blindly dial ATDnumber, I was
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
177 sometimes able to make a data call from a proper FreeCalypso test MS to a
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
178 Pirelli phone running its official fw: the destination phone would ring and
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
179 display an incoming call screen, but it said "data call". For this feat to
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
180 have happened, there must have been a BC IE in the MT SETUP message when the
47947e25f922 tmo/CSD-tests: document experimental findings
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
181 MO leg made a data call - hence the change between past and present bahaviour.