Microsoft KB Archive/250648

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Knowledge Base

Description of the Modem Responses Key in the Windows Me/98/95 Registry

Article ID: 250648

Article Last Modified on 1/27/2007


  • Microsoft Windows Millennium Edition
  • Microsoft Windows 98 Second Edition
  • Microsoft Windows 98 Standard Edition
  • Microsoft Windows 95

This article was previously published under Q250648


This article describes the following modem Responses key in the Windows Millennium Edition (Me), Windows 98, or Windows 95 registry:



The Responses key contains strings that the modem might report to Windows Me/98/95 in response to a command or during the connection process. The name of each subkey is the text of a single modem response, and its data is a 10-byte binary value specifying the meaning of the response to Windows in a coded format. The first two characters (byte 0) specify the meaning of the response code, using one of the following values:

Value Type Description
00 OK The modem accepted the previous command.
01 Negotiation Progress Status information about a new connection is being reported.
02 Connect A call is connected; the modem is in data mode.
03 Error The modem rejected the precious command.
04 No Carrier The call was disconnected.
05 No Dial Tone No dial tone is present.
06 Busy The dialed modem is busy.
07 No Answer The dialed modem did not answer.
08 Ring There is an incoming call.
1C Blacklisted The remote number does not answer as a modem.
ID Delayed The user should wait before trying this call again.

NOTE: The 1C and ID values are not included in Windows 95.

The second two characters (byte 1) specify information about a connection that is being made. It is used only for response codes of Negotiation Progress or Connect types, and is one of the following values:

Value Error control




Cellular protocol


00 -- -- --
01 -- X --
02 X -- --
03 X X --
08 -- -- X
09 -- X X
0A X -- X
0B X X X

The next eight characters (bytes 2-5) specify the modem-to-modem line speed negotiated in bits per second (bps). The characters represent a 32-bit integer, doubleword format (byte and word reversed). Common examples for this value include the following:

Bits per second String
2400 60 09 00 00
9600 80 25 00 00
14400 40 38 00 00
19200 00 4b 00 00
28800 80 70 00 00
33600 40 83 00 00
56000 C0 DA 00 00

The last eight characters (bytes 6-9) indicate that the modem is changing to a different port or Data Terminal Equipment (DTE) speed. Usually, this field is not used, because modems make connections at a "locked" port speed, regardless of the modem-to-modem or Data Communications Equipment (DCE) speed. However, for modems that support only "direct" modes, you can lower the DTE speed by specifying a negotiated DTE speed for a response code, using the same format as the DCE speed described in the preceding table.

Keywords: kbinfo KB250648