Cisco 3825 с платой NM-30DM= подключена к ATC NEC через NM-1CE1T1_PRI, для работы пула Dial-up. Канал поднят, модемы подключаются иногда, если доходит до авторизации то она проходит или сразу или долго висит окошко, поднимается линк, но данные между пользователем и cisco то идут то не идут, даже ping показывает большой timeout. Debug modem показывает что идут постоянные RETRAIN. Вместе с debug isdn показывают интересную картину - ниже. При этом ошибка S7_T203_EXPIRY: Lost communication with remote. идет постоянно каждые 10 сек, не зависимо есть ли кто на линии или нет.

Если ни кого на линии нет:
May  8 11:39:27: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.                                                                            
May  8 11:39:27: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=3            
May  8 11:39:27: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=5            
May  8 11:39:37: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.                                                                            
May  8 11:39:37: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=3            
May  8 11:39:37: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=5            
May  8 11:39:47: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.                                                                            
May  8 11:39:47: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=3            
May  8 11:39:47: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=5            
May  8 11:39:57: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.                                                                            
и так постоянно

если кто то на линии Dial-up

May  8 12:38:57: Modem 2/15 Mica: in modem state STEADY
May  8 12:38:57: Modem 2/15 Mica: Retrained to 53333/24000 (Tx/Rx)
May  8 12:38:58: Modem 2/15 Mica: in modem state SS_SHIFTINGSPEED
May  8 12:39:01: Modem 2/15 Mica: in modem state SS_RETRAINING
May  8 12:39:06: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.
May  8 12:39:06: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=11
May  8 12:39:06: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=18
May  8 12:39:10: Modem 2/15 Mica: in modem state STEADY
May  8 12:39:10: Modem 2/15 Mica: Retrained to 31200/31200 (Tx/Rx)
May  8 12:39:16: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.
May  8 12:39:16: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=11
May  8 12:39:16: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=18
May  8 12:39:17: Modem 2/15 Mica: in modem state SS_RETRAINING
May  8 12:39:26: Modem 2/15 Mica: in modem state STEADY
May  8 12:39:26: Modem 2/15 Mica: Retrained to 28800/28800 (Tx/Rx)
May  8 12:39:26: ISDN Se1/0:15 Q921: S7_T203_EXPIRY: Lost communication with remote.
May  8 12:39:26: ISDN Se1/0:15 Q921: Net TX -> RRp sapi=0 tei=0 nr=11
May  8 12:39:26: ISDN Se1/0:15 Q921: Net RX <- RRf sapi=0 tei=0 nr=18

c3825#show isdn status serial 1/0:15                                        
Global ISDN Switchtype = primary-net5                                        
ISDN Serial1/0:15 interface                                                  
        ******* Network side configuration *******                          
        dsl 1, interface ISDN Switchtype = primary-net5                      
    Layer 1 Status:                                                          
        ACTIVE                                                              
    Layer 2 Status:                                                          
        TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED      
    Layer 3 Status:                                                          
        0 Active Layer 3 Call(s)                                            
    Active dsl 1 CCBs = 0                                                    
    The Free Channel Mask:  0xFFFF7FFF                                      
    Number of L2 Discards = 0, L2 Session ID = 0                            
    Total Allocated ISDN CCBs = 0    
    

c3825#show control e1 1/0    
E1 1/0 is up.                                                    
  Applique type is Channelized E1 - balanced                      
  No alarms detected.                                            
  alarm-trigger is not set                                        
  Framing is CRC4, Line Code is HDB3, Clock Source is Internal.  
  Module type is Channelized E1/T1 PRI                            
  Version info Firmware: 0000001D, FPGA: 0                        
  Hardware revision is 0.0         , Software revision is 29      
  Protocol revision is 1                                          
  number of CLI resets is 1                                      
  Last clearing of alarm counters 18:07:31                        
    receive remote alarm  :    0,                                
    transmit remote alarm :    0,                                
    receive AIS alarm     :    0,                                
    transmit AIS alarm    :    0,                                
    loss of frame         :    0,                                
    loss of signal        :    0,                                
    Loopback test         :    0,                                
    transmit AIS in TS 16 :    0,                                
    receive LOMF alarm    :    0,                                
    transmit LOMF alarm   :    0,                                
  MIB data updated every 10 seconds.                              
  Data in current interval (448 seconds elapsed):                
     0 Line Code Violations, 2 Path Code Violations              

c3825# show inter ser 1/0:15                                            
Serial1/0:15 is up, line protocol is up (spoofing)                      
  Hardware is M32X with CSU/DSU                                          
  MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,                            
     reliability 255/255, txload 1/255, rxload 1/255                    
  Encapsulation HDLC, loopback not set                                  
  Last input 00:00:08, output 00:00:08, output hang never                
  Last clearing of "show interface" counters 18:07:48                    
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0  
  Queueing strategy: fifo                                                
  Output queue: 0/40 (size/max)                                          
  5 minute input rate 0 bits/sec, 0 packets/sec                          
  5 minute output rate 0 bits/sec, 0 packets/sec                        
     6543 packets input, 26340 bytes, 0 no buffer                        
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles              
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort      
     6551 packets output, 26340 bytes, 0 underruns                      
     0 output errors, 0 collisions, 0 interface resets                  
     0 output buffer failures, 0 output buffers swapped out              
     0 carrier transitions                                              
  Timeslot(s) Used:16, Transmitter delay is 0 flags                      
  

Части Конфига:

modem country mica russia

controller E1 1/0            
clock source internal      
pri-group timeslots 1-31    
!                            

interface Serial1/0:15              
no ip address                      
isdn switch-type primary-net5      
isdn protocol-emulate network      
isdn incoming-voice modem          
no keepalive                      
no fair-queue                      
no cdp enable                      
!

interface Group-Async0                  
ip unnumbered GigabitEthernet0/1      
encapsulation ppp                      
ip tcp header-compression              
no ip mroute-cache                    
async mode dedicated                  
peer default ip address pool pool30    
compress mppc                          
ppp authentication pap                
group-range 2/0 2/29                  
!                                      

line 2/0 2/29                          
modem Dialin                          
modem autoconfigure type mica        
!