Что бывает...

[Mike]

У меня 5614BXL/VR+. Пользуюсь им примерно год. Перед покупкой я прочитал кучу всего в Интренете и решил, что IDC это хорошо. Сначала я жил в Москве и модемом был в общем-то доволен. Правда я никогда не пользовался V.90 поскольку "наши люди на такси в булошную не ездят". А точнее скорость получалать не выше, чем V.34, а равномерность была совсем плохая. Потом у меня появилась возможность переехать в N-ск и тут началось. Ближайшая АТС старая развалюга, по всей видимости шаговая. Остальные станции в городе проапгрейдили, а к нашей пока только тянут оптику. Короче, модем здесь работает вполне прилично ночью и почти никак днём. Я считал старую АТС неизбежным злом и работал по ночам, терпеливо ожидая замены оборудования. Но тут приятель принёс свой комп, чтобы я "поковырялся". В нём стоял софтверный модем Acorp IRW2. Ради прикола я вставил модем себе и попробовал присоединиться днём. И о чудо! Там, где IDC бесконечно зависал и ретрейнился Acorp встал на 28800 и пёр как танк. Никаких провалов, абсолютно ровно 2,8К. Переконнектился несколько раз. Он либо не коннектился, либо вставал на 28-33К и качал ровно и чётко. Я решил провести чистое соревнование. Делал так, дозванивался и ставил скачиваться файл. Пропускал первые 100Кбайт и засекал время за которое скачаются следующие 500К, потом сразу перезванивал и делал то же самое другим модемом. И так 4 цикла. Вот результаты
Acorp 2,98K/s
IDC 1,77
Acorp 3,57
IDC 1,63
Acorp 2,28
IDC 1,54
Acorp 3,50
IDC 1,72
Итого в среднем Acorp: 2,99 IDC 1,66

В результате я решил пойти и купить себе такой же Акорп, благо он стоит 15 баксов. Однако встал вопрос, зачем я потратил в несколько раз больше, чтобы получить худший результат? И неужели Acorp, на котором нет даже DSP, действительно лучше?
Надеюсь получить ответы здесь...
Вот подробности: у провайдера стоит Cisco 3660
Строка инициализации IDC в первом и четвёртом случае ATM4+MS=11S50=14S13.7=1
и во втором и третьем ATM4+MS=11S50=14S13.7=1S91=15S210.7=1
Отдельно пробовал варьировать параметр S91 - без видимых улучшений.
Стасистика в порядке тестов:
Acorp Modem Booster 3.15
Today: 02.07.2003-20:52:28

Call Setup Result code...............: Data Answering signal detected
RX\TX level..........................: 16\11
Signal to noise level................: 30
Far echo delay.......................: 2
Transmit Carrier Negotiation Result..: V.34/V34bis
Receive Carrier Negotiation Result...: V.34/V34bis
Transmit Carrier symbol rate.........: 3200
Receive Carrier symbol rate..........: 3200
Transmit Carrier frequency...........: 1829
Receive Carrier frequency............: 1829
Initial transmit carrier data rate...: 28800
Initial receive carrier data rate....: 31200
Temporary carrier loss event count...: 0
Carrier Rate re-negotiation requested: 0
Carrier Rate re-negotiation granted..: 2
Carrier Retrains requested...........: 0
Carrier Retrains granted.............: 0
Final transmit carrier data rate.....: 28800
Final receive carrier data rate......: 26400
Error control........................: V.42 LAPM
Error control frame size.............: 128
Link timeouts........................: 0
Link naks............................: 71
Compression..........................: V.42bis
Compression dictionary...............: 1024
Chars send...........................: 35076
Chars received.......................: 1045240
TX chars lost........................: 0
RX chars lost........................: 0
TX frame count.......................: 911
RX frame count.......................: 8260
TX frame error count.................: 73
RX frame error count.................: 71
Termination reason...................: DTR drop
Call Waiting Counter.................: 0
......................................

Inpro IDC 2814/5614 BXL/VR Diagnostics, Version 1.0.1.30
02.07.2003 20:56:23 - Manual Diagnostics Request
--------------------------------------------------------
Modem type: IDC-5614BXL/VR+ (Plus) Firmware revision: V2.23

Time Online.................. 00:06:51
Termination Reason........... LINK DISCONNECT
Tx Rate (Last/Init/Min/Max).. 21600/21600/21600/21600 bps
Rx Rate (Last/Init/Min/Max).. 21600/21600/16800/21600 bps
Modulation................... V.34bis
Protocol/Compression......... LAP-M/V.42bis
Line Quality................. 13
Tx/Power Drop/Rx Level....... 10/3/27
SNR Last/Min/Max............. 10/9/10
Highest Rx/Tx State.......... 85/87
EQM Sum...................... 0000
RBS Pattern.................. NA
Rate Drop.................... NA
Digital Loss................. None
Retrains Issued/Granted/Auto. 1/0/0
Renegs Issued/Granted........ 5/0
FForwards/FBacks/Denied...... 2/3/0
Forced FB/FB after FF/MaxREJ. 3/0/9
Last dialed number........... P71313
Flex fail

Symbol Rate.................. 2400
Carrier Frequency Hz, Rx/Tx.. 1600/1600
EQM Value (Last/Min/Max)..... 13/3/56
EQM Hits..................... 0
EQM Last 10 Readings......... 15 16 15 14 15 14 15 14 14 14
Last Retrain/Reneg Status.... Local Rate Renegotiation
Last Retrain/Reneg Reason.... Local Fallforward due to Low EQM
Last Retrain/Reneg Time...... 1 minutes ago
Handshake Time/Retries....... 23 seconds/0
Non-linear Encoding, Rx/Tx... ON/ON
Precoding, Rx/Tx............. OFF/ON
Shaping, Rx/Tx............... ON/ON
Trellis Encoding, Tx......... 16 state
Pre-Emphasis Index, Tx....... 0
Band Edges Lower/Upper, Hz... 225/3825
Round trip delay, ms......... 0,6
Last Rx/Tx State............. 67/87
Energy at 3750Hz/Average .... 111/1003
Detection of 120 Hz Tones.... No
Detection of Dual PCM........ Yes
V.8 Negotiation Started...... Yes
V.8bis Success............... No
V.8bis CRe,CRd,CL,MS,ACK,NAK. No/No/No/No/No/No
Remote supports Symbol Rates. 2743 2800 3429 3000(L) 3000(H)
Remote supports Symbol Rates. 3200(L) 3200(H) 3429(Tx)
Remote supports Power Drop... Yes
Remote is CME Modem.......... No
Remote supports V.34bis...... Yes
Remote Max SR Difference..... 0 Symbol Rate Steps
Remote Frequency Source...... Internal
Error Correction Status Byte. ADP:R ODP:T
Error Correction Status Byte. SYNC UA:T UA:R SAMBE:T XID:T XID:R
Frames REJected, Last/Total.. 1/142
Frames Errors, Rx/Tx......... 142/3 (2,3%/0,3%)
Frames Count, Rx/Tx.......... 6173/955
Error Control Frame Size..... V.42 LAPM (128)
Error Control Timeouts....... 4
Error Control Link NAKs...... 3
Compression Dictionary Size.. V.42bis (1024)
Characters Received.......... 646947
Characters Sent.............. 22450
Average CPS, Rx/Tx........... 1574/54
Characters Lost, Rx/Tx....... 0/0
Estimated Noise Level, -dBm.. 37


Acorp Modem Booster 3.15
Today: 02.07.2003-21:02:13

Call Setup Result code...............: Data Answering signal detected
RX\TX level..........................: 16\12
Signal to noise level................: 33
Far echo delay.......................: 2
Transmit Carrier Negotiation Result..: V.34/V34bis
Receive Carrier Negotiation Result...: V.34/V34bis
Transmit Carrier symbol rate.........: 3200
Receive Carrier symbol rate..........: 3200
Transmit Carrier frequency...........: 1829
Receive Carrier frequency............: 1829
Initial transmit carrier data rate...: 28800
Initial receive carrier data rate....: 31200
Temporary carrier loss event count...: 0
Carrier Rate re-negotiation requested: 0
Carrier Rate re-negotiation granted..: 0
Carrier Retrains requested...........: 0
Carrier Retrains granted.............: 0
Final transmit carrier data rate.....: 28800
Final receive carrier data rate......: 31200
Error control........................: V.42 LAPM
Error control frame size.............: 128
Link timeouts........................: 0
Link naks............................: 6
Compression..........................: V.42bis
Compression dictionary...............: 1024
Chars send...........................: 24197
Chars received.......................: 703168
TX chars lost........................: 0
RX chars lost........................: 0
TX frame count.......................: 528
RX frame count.......................: 5547
TX frame error count.................: 10
RX frame error count.................: 6
Termination reason...................: DTR drop
Call Waiting Counter.................: 0
......................................



Inpro IDC 2814/5614 BXL/VR Diagnostics, Version 1.0.1.30
02.07.2003 21:11:00 - Manual Diagnostics Request
--------------------------------------------------------
Modem type: IDC-5614BXL/VR+ (Plus) Firmware revision: V2.23

Time Online.................. 00:07:06
Termination Reason........... LINK DISCONNECT
Tx Rate (Last/Init/Min/Max).. 21600/21600/21600/21600 bps
Rx Rate (Last/Init/Min/Max).. 19200/21600/ 2400/21600 bps
Modulation................... V.34bis
Protocol/Compression......... LAP-M/V.42bis
Line Quality................. 11
Tx/Power Drop/Rx Level....... 15/0/25
SNR Last/Min/Max............. 12/10/12
Highest Rx/Tx State.......... 85/87
EQM Sum...................... 0000
RBS Pattern.................. NA
Rate Drop.................... NA
Digital Loss................. None
Retrains Issued/Granted/Auto. 2/0/0
Renegs Issued/Granted........ 4/0
FForwards/FBacks/Denied...... 2/3/0
Forced FB/FB after FF/MaxREJ. 3/0/9
Last dialed number........... P71313
Flex fail

Symbol Rate.................. 2400
Carrier Frequency Hz, Rx/Tx.. 1600/1600
EQM Value (Last/Min/Max)..... 11/0/61
EQM Hits..................... 0
EQM Last 10 Readings......... 14 21 12 24 10 10 14 15 11 10
Last Retrain/Reneg Status.... Local Rate Renegotiation
Last Retrain/Reneg Reason.... Local Fallback due to High EQM
Last Retrain/Reneg Time...... 1 minutes ago
Handshake Time/Retries....... 19 seconds/0
Non-linear Encoding, Rx/Tx... ON/ON
Precoding, Rx/Tx............. OFF/ON
Shaping, Rx/Tx............... ON/ON
Trellis Encoding, Tx......... 16 state
Pre-Emphasis Index, Tx....... 0
Band Edges Lower/Upper, Hz... 225/3825
Round trip delay, ms......... 0,6
Last Rx/Tx State............. 67/87
Energy at 3750Hz/Average .... 161/1539
Detection of 120 Hz Tones.... No
Detection of Dual PCM........ Yes
V.8 Negotiation Started...... Yes
V.8bis Success............... No
V.8bis CRe,CRd,CL,MS,ACK,NAK. No/No/No/No/No/No
Remote supports Symbol Rates. 2743 2800 3429 3000(L) 3000(H)
Remote supports Symbol Rates. 3200(L) 3200(H) 3429(Tx)
Remote supports Power Drop... Yes
Remote is CME Modem.......... No
Remote supports V.34bis...... Yes
Remote Max SR Difference..... 0 Symbol Rate Steps
Remote Frequency Source...... Internal
Error Correction Status Byte. ADP:R ODP:T
Error Correction Status Byte. SYNC UA:T UA:R SAMBE:T XID:T XID:R
Frames REJected, Last/Total.. 1/170
Frames Errors, Rx/Tx......... 170/5 (2,8%/0,5%)
Frames Count, Rx/Tx.......... 6078/914
Error Control Frame Size..... V.42 LAPM (128)
Error Control Timeouts....... 5
Error Control Link NAKs...... 5
Compression Dictionary Size.. V.42bis (1024)
Characters Received.......... 609334
Characters Sent.............. 21544
Average CPS, Rx/Tx........... 1430/50
Characters Lost, Rx/Tx....... 0/0
Estimated Noise Level, -dBm.. 37



Acorp Modem Booster 3.15
Today: 02.07.2003-21:17:42

Call Setup Result code...............: Data Answering signal detected
RX\TX level..........................: 19\15
Signal to noise level................: 27
Far echo delay.......................: 2
Transmit Carrier Negotiation Result..: V.34/V34bis
Receive Carrier Negotiation Result...: V.34/V34bis
Transmit Carrier symbol rate.........: 3200
Receive Carrier symbol rate..........: 3200
Transmit Carrier frequency...........: 1829
Receive Carrier frequency............: 1829
Initial transmit carrier data rate...: 21600
Initial receive carrier data rate....: 24000
Temporary carrier loss event count...: 0
Carrier Rate re-negotiation requested: 0
Carrier Rate re-negotiation granted..: 3
Carrier Retrains requested...........: 0
Carrier Retrains granted.............: 1
Final transmit carrier data rate.....: 19200
Final receive carrier data rate......: 21600
Error control........................: V.42 LAPM
Error control frame size.............: 128
Link timeouts........................: 0
Link naks............................: 31
Compression..........................: V.42bis
Compression dictionary...............: 1024
Chars send...........................: 24454
Chars received.......................: 711107
TX chars lost........................: 0
RX chars lost........................: 0
TX frame count.......................: 791
RX frame count.......................: 5633
TX frame error count.................: 15
RX frame error count.................: 31
Termination reason...................: DisconnectFrameReceived
Call Waiting Counter.................: 0
......................................


Inpro IDC 2814/5614 BXL/VR Diagnostics, Version 1.0.1.30
02.07.2003 21:25:26 - Manual Diagnostics Request
--------------------------------------------------------
Modem type: IDC-5614BXL/VR+ (Plus) Firmware revision: V2.23

Time Online.................. 00:06:32
Termination Reason........... LINK DISCONNECT
Tx Rate (Last/Init/Min/Max).. 21600/16800/16800/21600 bps
Rx Rate (Last/Init/Min/Max).. 21600/21600/19200/21600 bps
Modulation................... V.34bis
Protocol/Compression......... LAP-M/V.42bis
Line Quality................. 36
Tx/Power Drop/Rx Level....... 15/0/25
SNR Last/Min/Max............. 9/9/9
Highest Rx/Tx State.......... 85/87
EQM Sum...................... 0000
RBS Pattern.................. NA
Rate Drop.................... NA
Digital Loss................. None
Retrains Issued/Granted/Auto. 0/0/0
Renegs Issued/Granted........ 2/0
FForwards/FBacks/Denied...... 1/1/0
Forced FB/FB after FF/MaxREJ. 1/0/8
Last dialed number........... P71313
Flex fail

Symbol Rate.................. 2400
Carrier Frequency Hz, Rx/Tx.. 1600/1600
EQM Value (Last/Min/Max)..... 36/14/65
EQM Hits..................... 0
EQM Last 10 Readings......... 31 31 36 33 38 38 40 35 30 33
Last Retrain/Reneg Status.... Local Rate Renegotiation
Last Retrain/Reneg Reason.... Local Fallforward due to Low EQM
Last Retrain/Reneg Time...... 4 minutes ago
Handshake Time/Retries....... 21 seconds/0
Non-linear Encoding, Rx/Tx... ON/ON
Precoding, Rx/Tx............. OFF/ON
Shaping, Rx/Tx............... ON/ON
Trellis Encoding, Tx......... 16 state
Pre-Emphasis Index, Tx....... 0
Band Edges Lower/Upper, Hz... 300/3825
Round trip delay, ms......... 1,0
Last Rx/Tx State............. 67/87
Energy at 3750Hz/Average .... 156/1500
Detection of 120 Hz Tones.... No
Detection of Dual PCM........ Yes
V.8 Negotiation Started...... Yes
V.8bis Success............... No
V.8bis CRe,CRd,CL,MS,ACK,NAK. No/No/No/No/No/No
Remote supports Symbol Rates. 2743 2800 3429 3000(L) 3000(H)
Remote supports Symbol Rates. 3200(L) 3200(H) 3429(Tx)
Remote supports Power Drop... Yes
Remote is CME Modem.......... No
Remote supports V.34bis...... Yes
Remote Max SR Difference..... 0 Symbol Rate Steps
Remote Frequency Source...... Internal
Error Correction Status Byte. ADP:R ODP:T
Error Correction Status Byte. SYNC UA:T UA:R SAMBE:T XID:T XID:R
Frames REJected, Last/Total.. 1/145
Frames Errors, Rx/Tx......... 145/5 (2,4%/0,5%)
Frames Count, Rx/Tx.......... 6080/912
Error Control Frame Size..... V.42 LAPM (128)
Error Control Timeouts....... 5
Error Control Link NAKs...... 5
Compression Dictionary Size.. V.42bis (1024)
Characters Received.......... 617448
Characters Sent.............. 21638
Average CPS, Rx/Tx........... 1575/55
Characters Lost, Rx/Tx....... 0/0
Estimated Noise Level, -dBm.. 34



Acorp Modem Booster 3.15
Today: 02.07.2003-21:29:45

Call Setup Result code...............: Data Answering signal detected
RX\TX level..........................: 17\11
Signal to noise level................: 33
Far echo delay.......................: 3
Transmit Carrier Negotiation Result..: V.34/V34bis
Receive Carrier Negotiation Result...: V.34/V34bis
Transmit Carrier symbol rate.........: 3200
Receive Carrier symbol rate..........: 3200
Transmit Carrier frequency...........: 1829
Receive Carrier frequency............: 1829
Initial transmit carrier data rate...: 28800
Initial receive carrier data rate....: 31200
Temporary carrier loss event count...: 0
Carrier Rate re-negotiation requested: 0
Carrier Rate re-negotiation granted..: 0
Carrier Retrains requested...........: 0
Carrier Retrains granted.............: 0
Final transmit carrier data rate.....: 28800
Final receive carrier data rate......: 31200
Error control........................: V.42 LAPM
Error control frame size.............: 128
Link timeouts........................: 0
Link naks............................: 21
Compression..........................: V.42bis
Compression dictionary...............: 1024
Chars send...........................: 22048
Chars received.......................: 631422
TX chars lost........................: 0
RX chars lost........................: 0
TX frame count.......................: 479
RX frame count.......................: 4996
TX frame error count.................: 12
RX frame error count.................: 21
Termination reason...................: DTR drop
Call Waiting Counter.................: 0
......................................


Inpro IDC 2814/5614 BXL/VR Diagnostics, Version 1.0.1.30
02.07.2003 21:38:13 - Manual Diagnostics Request
--------------------------------------------------------
Modem type: IDC-5614BXL/VR+ (Plus) Firmware revision: V2.23

Time Online.................. 00:06:29
Termination Reason........... LINK DISCONNECT
Tx Rate (Last/Init/Min/Max).. 21600/21600/21600/21600 bps
Rx Rate (Last/Init/Min/Max).. 19200/ 9600/ 9600/21600 bps
Modulation................... V.34bis
Protocol/Compression......... LAP-M/V.42bis
Line Quality................. 9
Tx/Power Drop/Rx Level....... 15/0/27
SNR Last/Min/Max............. 10/10/10
Highest Rx/Tx State.......... 85/87
EQM Sum...................... 0000
RBS Pattern.................. NA
Rate Drop.................... NA
Digital Loss................. None
Retrains Issued/Granted/Auto. 0/0/0
Renegs Issued/Granted........ 5/0
FForwards/FBacks/Denied...... 3/2/0
Forced FB/FB after FF/MaxREJ. 2/1/8
Last dialed number........... P71313
Flex fail

Symbol Rate.................. 2400
Carrier Frequency Hz, Rx/Tx.. 1600/1600
EQM Value (Last/Min/Max)..... 9/0/57
EQM Hits..................... 0
EQM Last 10 Readings......... 8 8 8 9 9 9 9 14 12 11
Last Retrain/Reneg Status.... Local Rate Renegotiation
Last Retrain/Reneg Reason.... Local Fallback due to High EQM
Last Retrain/Reneg Time...... 3 minutes ago
Handshake Time/Retries....... 29 seconds/0
Non-linear Encoding, Rx/Tx... OFF/ON
Precoding, Rx/Tx............. OFF/ON
Shaping, Rx/Tx............... ON/ON
Trellis Encoding, Tx......... 16 state
Pre-Emphasis Index, Tx....... 0
Band Edges Lower/Upper, Hz... 225/3825
Round trip delay, ms......... 0,6
Last Rx/Tx State............. 67/87
Energy at 3750Hz/Average .... 142/1346
Detection of 120 Hz Tones.... No
Detection of Dual PCM........ Yes
V.8 Negotiation Started...... Yes
V.8bis Success............... No
V.8bis CRe,CRd,CL,MS,ACK,NAK. No/No/No/No/No/No
Remote supports Symbol Rates. 2743 2800 3429 3000(L) 3000(H)
Remote supports Symbol Rates. 3200(L) 3200(H) 3429(Tx)
Remote supports Power Drop... Yes
Remote is CME Modem.......... No
Remote supports V.34bis...... Yes
Remote Max SR Difference..... 0 Symbol Rate Steps
Remote Frequency Source...... Internal
Error Correction Status Byte. ADP:R ODP:T
Error Correction Status Byte. SYNC UA:T UA:R SAMBE:T XID:T XID:R
Frames REJected, Last/Total.. 1/166
Frames Errors, Rx/Tx......... 166/0 (1,5%/0,0%)
Frames Count, Rx/Tx.......... 11347/952
Error Control Frame Size..... V.42 LAPM (64)
Error Control Timeouts....... 1
Error Control Link NAKs...... 0
Compression Dictionary Size.. V.42bis (1024)
Characters Received.......... 644281
Characters Sent.............. 22345
Average CPS, Rx/Tx........... 1656/57
Characters Lost, Rx/Tx....... 0/0
Estimated Noise Level, -dBm.. 37

[Technical Support]

Сразу же бросается в глаза разница в качестве принимаемого сигнала:

Signal to noise level................: 30

SNR Last/Min/Max............. 10/9/10

И так во всех статистиках: примерно 10 дБ против примерно 30 дБ. Всё остальное определяется именно этим.

Поскольку столь разительно отличающиеся друг от друга результаты получены на одной линии, разумно предположить проблемы в аналоговой части Вашего модема. Они могут быть как "внутренними" (например, пробитый стабилитрон), так и внешними, наведёнными. Из внешних, например, такая: помехи при отсутствии заземления. Попробуйте удалить конденсаторы C2, C3 (рядом с гнездом для телефона) или отключить заземление в кабеле, соединяющем модем с последовательным портом.

Если не поможет - модем в ремонт.
_________________
Inpro
Technical Support