Issue:
When initiating a dial-out connection using Dialup Networking (DUN), Windows responds with an error: No Response from Modem

Cause:
Certain modems, when in 'command mode', force a 'Clear To Send (CTS)' drop while transmitting a response to an AT command. When such a modem is connected to a Perle833 Server in 'dial-out' mode. extranious 'null characters' are prepended to the response. The Win9x or WinNT Dial Up Networking (DUN) software will, via the manufacturer supplied 'mdmxxxxx.inf' definitions, remove and characters that are pre-pended to a response, but not nulls.
The following modems are known to exibit this problem:
Motorola BitSURFR [Pro] [Ex]
BT IGNITION
Resolution

Solution:
Addition of a single 'null-filter' to the Motorola supplied INF file prevents the 'unrecognized response' loop, as reported in ModemLog.txt. Correct transition to the dial state is then possible. Care must be taken to ensure proper re-installation of the modified file. An example, for the Motorola 'BitSURFR Pro', using the 'MOT1116C.INF' file, is provided below.
Here is a modified version of 'MOT1116C.INF', called 'MDMMOTOR.INF'. 

[Version] 
Signature="$CHICAGO$" 
Class=Modem 
Provider=%Mfg% 
[Strings] 
Mfg = "Motorola" 
Modem1PNP="Motorola BitSURFR PRO Plug & Play" 
Modem1="Motorola BitSURFR PRO" 
[ControlFlags] 
ExcludeFromSelect=SERENUM\MOT1116 
[Modem1.NoResDup] 
UNIMODEM6904ECE8 
[Manufacturer] 
%Mfg% = Models 
[Models] 
%Modem1PNP% = Modem1, SERENUM\MOT1116 ; Motorola BitSURFR PRO EXTERNAL
%Modem1% = Modem1, UNIMODEM6904ECE8 ; Motorola BitSURFR PRO EXTERNAL
[Modem1] ; Motorola BitSURFR PRO 
AddReg=All, MfgAddReg, Modem1.AddReg, EXTERNAL 
[Modem1.AddReg] ; Motorola BitSURFR PRO 
HKR,, Properties, 1, 00,00,00,00, ff,00,00,00, 00,00,00,00, 00,00,00,00, 00,00,00,00, 30,00,00,00, 00,c2,01,00, 00,fa,00,00 
HKR, Init, 2,, "AT &F &C1 &D2 E0 V1" 
[All] 
HKR,,FriendlyDriver,,Unimodem.vxd 
HKR,,DevLoader,,*vcomm 
HKR,,PortSubClass,1,02 
HKR,,ConfigDialog,,modemui.dll 
HKR,,EnumPropPages,,"modemui.dll,EnumPropPages" 
HKR, Init, 1,, "AT" 
HKR, Responses, "", 1, 01, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "OK", 1, 00, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "ERROR", 1, 03, 00, 00,00,00,00, 00,00,00,00 HKR, Responses, "0", 1, 00, 00, 00,00,00,00, 00,00,00,00 HKR, Responses, "2", 1, 08, 00, 00,00,00,00, 00,00,00,00 HKR, Responses, "4", 1, 03, 00, 00,00,00,00, 00,00,00,00 
[EXTERNAL] 
HKR,, DeviceType, 1, 01 
[MfgAddReg] 
HKR,, InactivityScale, 1, 3c,00,00,00 
HKR, Init, 2,, "AT&F&D2&C1\V1S0=0E0V1" 
HKR, Monitor, 1,, "ATS0=0" 
HKR, Monitor, 2,, "None" 
HKR, Hangup, 1,, "ATH" 
HKR, Answer, 1,, "ATA" 
HKR,, Reset,, "AT&F" 
HKR, Settings, Prefix,, "AT" 
HKR, Settings, Terminator,, "" 
HKR, Settings, DialPrefix,, "D" 
HKR, Settings, DialSuffix,, ";" 
HKR, Settings, SpeakerVolume_Low,, "L0" 
HKR, Settings, SpeakerVolume_Med,, "L2" 
HKR, Settings, SpeakerVolume_High,, "L3" 
HKR, Settings, SpeakerMode_Off,, "M0" 
HKR, Settings, SpeakerMode_Dial,, "M1" 
HKR, Settings, SpeakerMode_On,, "M2" 
HKR, Settings, SpeakerMode_Setup,, "M3" 
HKR, Settings, FlowControl_Off,, "\Q" 
HKR, Settings, FlowControl_Hard,, "\Q3" 
HKR, Settings, FlowControl_Soft,, "\Q1" 
HKR, Settings, ErrorControl_On,, "\N6" 
HKR, Settings, ErrorControl_Off,, "\N0" 
HKR, Settings, ErrorControl_Forced,, "\N2" 
HKR, Settings, Compression_On,, "%%C1" 
HKR, Settings, Compression_Off,, "%%C0" 
HKR, Settings, Pulse,, "P" 
HKR, Settings, Tone,, "T" 
HKR, Settings, Blind_Off,, "X4" 
HKR, Settings, Blind_On,, "X3" 
HKR, Settings, CallSetupFailTimer,, "S7=<#>" 
HKR, Settings, InactivityTimeout,, "\T<#>" 

HKR, Responses, "",1, 01, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "", 1, 01, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "", 1, 01, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "OK",1, 00, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "RING",1, 08, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO CARRIER",1, 04, 00, 00,00,00,00,00,00,00,00 
HKR, Responses, "ERROR",1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO DIALTONE",1, 05, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "BUSY",1, 06, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO ANSWER",1, 07, 00, 00,00,00,00,00,00,00,00 
HKR, Responses, "CONNECT", 1, 02, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "OK", 1, 00, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "RING", 1, 08, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO CARRIER", 1, 04, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "ERROR", 1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO DIALTONE", 1, 05, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO DIAL TONE",1, 05, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "BUSY", 1, 06, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "NO ANSWER", 1, 07, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "FAX", 1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "DATA", 1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "VOICE", 1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "RINGING", 1, 01, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "DELAYED", 1, 03, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "CONNECT", 1, 02, 00, 00,00,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 1200", 1, 02, 00, B0,04,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 2400", 1, 02, 00, 60,09,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 7200", 1, 02, 00, 20,1C,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 9600", 1, 02, 00, 80,25,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 12000", 1, 02, 00, E0,2E,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 14400", 1, 02, 00, 40,38,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 16800", 1, 02, 00, A0,41,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 19200", 1, 02, 00, 00,4B,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 21600", 1, 02, 00, 60,54,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 24000", 1, 02, 00, C0,5D,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 26400", 1, 02, 00, 20,67,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 28800", 1, 02, 00, 80,70,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 38400", 1, 02, 00, 00,96,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 57600", 1, 02, 00, 00,E1,00,00, 00,00,00,00 
HKR, Responses, "CONNECT 115200", 1, 02, 00, 00,C2,01,00, 00,00,00,00 

Thus 'HKR, Responses, "",1, 01, 00, 00,00,00,00, 00,00,00,00' has been added in two places, as indicated above. 
The 'MDMMOTOR.INF' file replaces 'MOT1116C.INF', thus this file and 'DRVDATA.BIN' and 'DRVIDX.BIN' must be removed from the 'C:\WINDOWS\INF\' directory. 
Also, all previously installed 'Motorola BitSURFR PRO' modems must be uninstalled/removed via START/Settings/Control Panel/Modems/Remove.. 
Next, install MDMMOTOR.INF via 'START/Settings/Control Panel/Add New Hardware'. 
Finally, (re)install the 'Motorola BitSURFR PRO' on the dial-out port via 'START/Settings/Control Panel/Modems/Add..' 
After doing all that, your Win9x registry will have this additional entry for 'port n' (use regedit.exe): HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\
Modem\000n\Responses\ 01 00 00 00 00 00 00 00 00 
C:\WINDOWS\ModemLog.txt will now say:

10-20-1998 16:33:04.85 - Motorola BitSURFR PRO in use. 
10-20-1998 16:33:04.85 - Modem type: Motorola BitSURFR PRO 
10-20-1998 16:33:04.85 - Modem inf path: MDMMOTOR.INF 
10-20-1998 16:33:04.86 - Modem inf section: Modem1 
10-20-1998 16:33:04.91 - 19200,N,8,1 
10-20-1998 16:33:04.95 - 19200,N,8,1 
10-20-1998 16:33:04.97 - 19200,N,8,1 
10-20-1998 16:33:04.98 - Initializing modem. 
10-20-1998 16:33:04.98 - Send: AT 
10-20-1998 16:33:05.11 - Recv: AT 
10-20-1998 16:33:05.19 - Recv: <00> 
10-20-1998 16:33:05.19 - Interpreted response: Informative 
10-20-1998 16:33:05.22 - Recv: OK 
10-20-1998 16:33:05.22 - Interpreted response: Ok 
10-20-1998 16:33:05.22 - Send: AT &F &C1 &D2 E0 V1 
10-20-1998 16:33:05.39 - Recv: AT &F &C1 &D2 E0 V1 
10-20-1998 16:33:05.54 - Recv: <00> 
10-20-1998 16:33:05.54 - Interpreted response: Informative 
10-20-1998 16:33:05.57 - Recv: <00> 
10-20-1998 16:33:05.57 - Interpreted response: Informative 
10-20-1998 16:33:05.58 - Recv: <00> 
10-20-1998 16:33:05.58 - Interpreted response: Informative 
10-20-1998 16:33:05.61 - Recv: OK 
10-20-1998 16:33:05.61 - Interpreted response: Ok 
10-20-1998 16:33:05.61 - Send: ATS7=60\Q3 
10-20-1998 16:33:05.85 - Recv: <00> 
10-20-1998 16:33:05.85 - Interpreted response: Informative 
10-20-1998 16:33:05.88 - Recv: OK 
10-20-1998 16:33:05.88 - Interpreted response: Ok 
10-20-1998 16:33:05.88 - Dialing. 
10-20-1998 16:33:05.88 - Send: ATD; 
10-20-1998 16:33:06.10 - Recv: <00> 
10-20-1998 16:33:06.10 - Interpreted response: Informative 
10-20-1998 16:33:06.12 - Recv: OK 
10-20-1998 16:33:06.12 - Interpreted response: Ok 
10-20-1998 16:33:06.21 - Dialing. 
10-20-1998 16:33:06.21 - Send: ATD# 
10-20-1998 16:33:06.48 - Recv: <00> 
10-20-1998 16:33:06.48 - Interpreted response: Informative 
10-20-1998 16:33:06.51 - Recv: NO DIALTONE 
10-20-1998 16:33:06.51 - Interpreted response: No Dialtone 
10-20-1998 16:33:09.11 - Session Statistics: 
10-20-1998 16:33:09.11 - Reads : 69 bytes 
10-20-1998 16:33:09.11 - Writes: 44 bytes 
10-20-1998 16:33:09.11 - Motorola BitSURFR PRO closed.