hi, i just encountered the following problem: the network assigns me from TS 1 to TS 3 it worked, but not when it did another assigment from TS 3 to TS4. i just got noise instead of valid SACCH frames. TS Chg forth: 1 -> 3 | 1856 ... TS Chg forth: 3 -> 4 | 1875 this is the wireshark trace of both assignments. they only differ in the assigned slot: Frame 3225: 81 bytes on wire (648 bits), 81 bytes captured (648 bits) Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00) Internet Protocol Version 4, Src: 127.0.0.1 (127.0.0.1), Dst: 127.0.0.1 (127.0.0.1) User Datagram Protocol, Src Port: 52261 (52261), Dst Port: gsmtap (4729) GSM TAP Header, ARFCN: 34 (Downlink), TS: 1, Channel: SDCCH/8 (0) Link Access Procedure, Channel Dm (LAPDm) GSM A-I/F DTAP - Assignment Command Protocol Discriminator: Radio Resources Management messages DTAP Radio Resources Management Message Type: Assignment Command (0x2e) Channel Description 2 - Description of the First Channel, after time 0000 1... = TCH/F + FACCH/F and SACCH/F .... .011 = Timeslot: 3 000. .... = Training Sequence: 0 ...1 .... = Hopping channel: Yes Hopping channel: MAIO 0 Hopping channel: HSN 0 Power Command 0... .... = Spare: 0 .0.. .... = EPC_mode: Channel(s) not in EPC mode ..0. .... = FPC_EPC: FPC not in use/C not in use for uplink power control ...0 0101 = POWER LEVEL: 5 Frequency List - Frequency List, after time Element ID: 5 Length: 16 00.. 000. = Format Identifier: bit map 0 (0x00) List of ARFCNs = 99 34 Channel Mode - Mode of the First Channel(Channel Set 1) Element ID: 99 Channel Mode: speech full rate or half rate version 2(GSM EFR) (33) No. Time Source Destination Protocol Info 3243 464.672890 127.0.0.1 127.0.0.1 LAPDm I, N(R)=1, N(S)=2(DTAP) (RR) Assignment Command Frame 3243: 81 bytes on wire (648 bits), 81 bytes captured (648 bits) Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00) Internet Protocol Version 4, Src: 127.0.0.1 (127.0.0.1), Dst: 127.0.0.1 (127.0.0.1) User Datagram Protocol, Src Port: 52261 (52261), Dst Port: gsmtap (4729) GSM TAP Header, ARFCN: 99 (Downlink), TS: 3, Channel: FACCH/F (0) Link Access Procedure, Channel Dm (LAPDm) GSM A-I/F DTAP - Assignment Command Protocol Discriminator: Radio Resources Management messages DTAP Radio Resources Management Message Type: Assignment Command (0x2e) Channel Description 2 - Description of the First Channel, after time 0000 1... = TCH/F + FACCH/F and SACCH/F .... .100 = Timeslot: 4 000. .... = Training Sequence: 0 ...1 .... = Hopping channel: Yes Hopping channel: MAIO 0 Hopping channel: HSN 0 Power Command 0... .... = Spare: 0 .0.. .... = EPC_mode: Channel(s) not in EPC mode ..0. .... = FPC_EPC: FPC not in use/C not in use for uplink power control ...0 0101 = POWER LEVEL: 5 Frequency List - Frequency List, after time Element ID: 5 Length: 16 00.. 000. = Format Identifier: bit map 0 (0x00) List of ARFCNs = 99 34 Channel Mode - Mode of the First Channel(Channel Set 1) Element ID: 99 Channel Mode: speech full rate or half rate version 2(GSM EFR) (33) any idea why this does not work? i used the "[WIP] Ugly hack to compensate lost time on TS change (high TS -> low TS)" path. regards, andreas