Modem Initialization Strings:

If you are having trouble staying online and getting disconnected frequently.  It could be the phone lines cannot handle the higher speed transmissions.  Turning your modem speed down can sometimes solve this problem.  Below is a list of initialization strings for various modems.  Find your modem in the list and enter one of the associated initialization strings in you modems properties. 

In Windows you can find out what type of modem you have by going to the Control Panel and then click on 'Modems' or 'Phone and Modem Options'.

If you are not sure where to enter these initialization strings... CLICK HERE.

 
Manufacturer Initialization String(s)
3Com See US Robotics
21st Century 56k +MS=56,1,300,40000
ABC +MS=V34,1,300,33600
ActionTec S38=0 (PCMCIA Lucent Venus)
+MS=V34,1,300,33600 (PCI/ISA Cirrus)
ActionTec Call Waiting Modem S38=0S109=0 (Disables v90- Lucent)
Ambient See Cirrus Logic
AC-Link
(Manufactured by:
   Motorola,
   PC Tel,
   Conexant,
   Smart Link,
   AMR,
   and GVC)
+MS=V34
Acer Modem Master 56k: AT&F&C1Q0V1
 
AcerModem 56 data-fax-voice modem (Any 56k/v90 Modem):
String:
&N10
&N11
&N12
&N13
&N14
&N15
&N16
&N17
&N18
&N19
&N20
&N21
&N22
&N23
&N24
&N25
Port Speed Set:
19200
21600
24000
26400
28800
31200
33600
33333
37333
41333
42666
44000
45333
46666
44000
48000
AMR (Audio Modem Riser) Modems Smart Link AMR:
+MS=34,0,4800,33600 (Disable V.90)

+MS=V34 (Disables V.90)
AOPEN (Acer) PCI-
F56-S: N0S37=12 (PCTel Chipset)
FM56-SM: +MS=V34 (Conexant Chip)
FM56-PM: +MS=V34 (Conexant Chip)
ISA-
FM56-ITU/2: N0S37=12 (Hardware Chipset using PCTel Commands)
External-
FM56-EX/2: +MS=V34 (Conexant Chip)
Apple: Global Village
   (including: Geoport & Teleport)
AT&F1W1 (Older models)
AT&F1W2 - Global Village Init
 
Apple: G3, G4, or iMac Internal Modem    (GV Internal) To update modem drivers use: Mac Modem Update Wizard
[To set a iMac or G3/4 to v.34 simply select the "iMac (v34 only)" modem definition in the modem control panel.]
AT&T WinModem See LT Winmodem
Aureal SoundCom *MM12 (Disable v.90)
Avtek Megamodem 2000 (CD 2000) +MS=(11,12,56),1,300,40000
Aztech PCI V90:
+MS=V34 (V90 disable- Rockwell)
-V90=0 (V90 disable- Lucent)

UM9800 V90 USB:
+MS=(34,90),1,75,40000 or
+MS=34,1,33600,33600
Boca +MS=11,1
Boca Kflex V2.060.K +MS=11,1
Broadcom BCM S51=31 (Disable X2/V90)
S51=95 (Disable X2)
S51=63 (Disable V90)
Cirrus Logic (Now Ambient) +MS=V34,1,0,33600 (x2/v90 off)
+MS=X2,0 (disable v90 only)
CLMD56 see x2/v90 US Robotics
Compaq -HSP/Micromodem (see HSP)

-Rockwell/Conexant HCF (see HCF)

-LT Winmodem (see Lucent)

-Compaq DF (Lucent chipset): Driver version 5.75 update may solve issues. Suggested strings are: S38=0 or S37=0
Conexant (Fomerly Rockwell) +MS=V34 (disables V90)
+MS=V90 (forces V90)
+MS=(k56 or V90),1,75,33600,75,40000
(forces V90 or K56)
+ES=1,0,1; (disable v42)
Creative Labs ModemBlaster +MS=V34 (disable v90- Conexant)
Diamond (Supra) SupraMax 56i PCI:
AT&F+MR=1;+MS=V34,0 (Disable v.90)
AT&F+MR=1;+MS=V90,0 (Enable v.90)

Supra PCI:
AT&F+MS=11,0 (Disable v.90)

Supra Express PCI: AT&FW2+MS=11,1 (disable V.90)

SupraExpress USB:
S38=0 (Disable v.90)
AT&FS9=20S10=60 (Not sure what is does, but it makes the SupraExpress USB connect with line noise).

Diamond Voice PCI:
-V90=0 (Disable v.90)
Dyna Link 56k PnP +MS=11 (Disable V.90)
ESS (Also called Teledrive) +MS=11,0
Gateway -56K PCI Modem Designed for the Internet uses Lucent Chipset.

-AC Link uses HSP Chipset.

-56k PCI Voice Modem SF-1156IV + R9A: +MS=V90,1,75,33600,75,40000 (Forces V.90)

-GTW V.92: +MS=V34 (Disables V.92)
Hayes Note: Older modems are v.34 only.

+MS=11,1,2400,33600 (Disables K-Flex for the legacy 56kflex/v34 modems)

+MS=12,1,300,40000 (Disables V.90)
HSP (see PC Tel) N0S37=14 (forces V90)
N0S37=12 (disables V90)

Alternate String:
+MS=(V=34,V90),1,300,40000

HSP AMR:
+MS=V90,1,300,40000 (Forces V.90)
+MS=V34 (Disables V.90)
Intel Modems
   (MD563X, MD566X and, MD567X)
Disable V.90:
+MS=V34,1,0,0
or
+MS=V34,1,300,28800
K-Flex Generic (K-Flex) AT+MS=56,1,300,42000
Lucent AMR +MS=V34 (Disables V.90)
Lucent Venus S38=0 (Disable K-Flex)
S109=0 (Disables V.90)
S109=2 (Disables X2)
/N2 (Disable V.42)
LT Win or Lucent Winmodem (Mars or Apollo LT Chipset) -V90=0 (Disables V.90)
S38=0 (Disables K-Flex)
S37=0 (Sets up stream rate to default)
/N2 (Disable V.42)
Maestro Jetstream External K56 +MS=56,1,300,40000
Micromodem (56 HSP) See PcTel for more info.
Micron X2 AT&F1&K0&I0S33=325S15=128S27=64
Motorola SM56 *MM0 (Disables V90)
MDP3900 (latest shipped model)
MDP3858 (older version of 3900)
MDxxxxx (generic Conexant)
First: +MS=V90 or +MS=V90, 0
(disables K-Flex and sets to v.90)

If not then: +MS=V34 (sets v.34)

MDP 3858 SP Modem (Packard-Bell):
+ms=V90,1,75,33600,75,40000
MDP (Lucent Chipset) -V90=0 (turns off v.90)
MSP +MS=V34
MWave (IBM Aptiva) -SSE1
%C (Disable V.42bis/MNP 5)
\N3 (Disable V.42)
\N5 (Disable MNP)
Control Connection Speed:
S28=18 for 26.4Kbps
S28=17 for 24.0Kbps
S28=16 for 21.6Kbps
S28=15 for 19.2Kbps
NEC -V90=0
Netcruiser 56000 External Data/Fax/Voice Modem +MS=(11,12,56),1,300,40000
Newcom (Atlas) 56K Internal: S32=34 (disable X2)
-Use USR commands
Packard Bell Sound 3 or 4 AT&F1&C1X4
PCI based software modem.  
PC Tel (HSP Chipset) N0S37=14 (forces V90)
N0S37=12 (disables V90)
Psion Dacom Global Goldcard
(V.90 56K)
+MS=11,1,2400,33600
(Uses Hayes commands)
Riptide (Audio/Modem Combo)  
Rockwell HCF or Soft56k (Conexant Chipset) +MS=V34 (disables V90)
+MS=V90 (forces V90)

S95=1 is supposed fix fix issues with connecting, slow connections, slow transfer rates, and hang ups.
Rockwell Dual (Conexant Chipset) AT+MS=56 (Disables V.90)
AT+MS=12 (Disables Kflex)
AT+MS=11 (Disables V.90 and Kflex)
Rockwell Generic Chipset (Conexant Chipset) +MS=V34 (disable v90) or
+MS=11,1 (disable v90)

Rockwell RCV288 and ACF modem: at+a8e=,,,1

+ES=1,0,1; (disable v42)
Q6 (disable v.42)
S95=1 (report port speed)
Teledrive ESS Modem Chipset. See ESS.
Telepath (X2 Winmodem) S32=34 (v.90 on, X2 off; using V.34)
Use US Robotics strings (see USR).
US Robotics (Formerly 3Com) S32=66 (v.90 off X2 on )
S32=34 (v.90 on, X2 off; using V.34)
S32=98 (v.90 off, X2 off; using V.42)
S15=128 (Disables V.42bis compression.)
S10=100S25=200 (Increases line noise time out to 100 ms.)
s10=120 ( Makes modem wait 120 ms before hanging up. Good for disconnection issues.)
&k1 ( Forces Data Compression )
&k0 ( Disables Data Compression )
&m5 ( Forces Error Correction )
US Robotics Courier S58=1 (Disable X2)
S27=32(Disable V.42)
S58=32 (Disable V.90)
S58=33 (Disable V.90 & X2)
Venus PCMCIA (see LT Venus) S38=0
Viking PC Card (PCMCIA)-
+MS:11,1,300,33600,0,0 (Disable v.90)
+MS=V34 (Disable v.90)
VIVA +MS=11,1
X2 type generic modem see US Robotics
Winmodem S38=0 (disables K-Flex)
Xircom  
Zoom S109=0
Zoom 2919: AT$$CW3
PCI: -V90=0 or +MS=V34 (disables V.90)
USB: +MS=V34
(disables V.90)
External: +MS=11,1
(disables V.90)