TECHNICAL REFERENCE FOR HAYES (TM) MODEM USERS15 Sept 1992Version P2.0Hayes Microcomputer Products, Inc.P.O. Box 105203Atlanta, Georgia 30348 U.S.A.(c) 1990, 1992 Hayes Microcomputer Products, Inc.All rights reserved.44-00012 AA H32 (BBS Version)Note: This version of the "Technical Reference for Hayes Modem Users" is a special version edited for bulletin-board downloading. As a plain ASCII character file, it therefore cannot contain any of the illustrations and graphic elements provided in the printed version.------------------------------------------------------------------------I - Internal Memory TestsThe various forms of the I command instruct the modem to query its memory for information about itself. The results of these tests are frequently used by programmers to determine compatibility with software. Because these commands request information about the modem's firmware, they are not run when a connection has been established with a remote modem.I0 - Display Product CodeThis option reports the product code of the modem to the DTE. The modem produces information text dependent upon its highest DCE line speed. The responses below are examples:Result Codes     Description------------------------------------------------------------------------300              Smartmodem 300.120              Smartmodem 1200, Smartmodem 1200B, Smartmodem 1200C,                  Smartmodem 1200A.240              Smartmodem 2400, Smartmodem 2400B, Smartmodem 2400P,                  Smartmodem 2400Q, Smartmodem 2400M, V-series Smartmodem                  2400, V-series Smartmodem 2400B, V-series Smartmodem                  2400 Quad, V-series Smartmodem 2400M, Smartmodem OPTIMA                  (TM) 24, Smartmodem OPTIMA 24 + FAX96,                  ACCURA (TM) 2400 EC/FAX96.960              Smartmodem 9600, V-series Smartmodem 9600, V-series                  Smartmodem 9600B, V-series ULTRA (TM) Smartmodem 2400,                  V-series ULTRA Smartmodem 9600, V-series ULTRA 24 with                  Express 96, Smartmodem OPTIMA 9600, Smartmodem                  OPTIMA 96 + FAX96, ACCURA 9600 EC/FAX96.  14400            V-series ULTRA Smartmodem 14400, Smartmodem OPTIMA 144,                  Smartmodem OPTIMA 144 + FAX144, ACCURA 14400 EC/FAX144. ------------------------------------------------------------------------I1- Display ROM ChecksumThe I1 command instructs the modem to calculate the value of the ROM checksum. The response is a number, the sum of all of the bytes in ROM.I2 - Perform ROM ChecksumThis command instructs the modem to verify the ROM checksum. Depending on whether the ROM checksum has been found to be correct, the modem produces text that resembles a result code. The modem memory test compares the ROM checksum and tests it against the correct sum, also stored in ROM. Rather than returning a numeric value as in I1, the I2 command generates a result code. When the checksum is valid, the response is: OK. When the ROM checksum fails, the modem responds with ERROR.I4 -  Identify Product FeaturesThe capabilities and features of the modem are encoded into a string of text that consists of several strings that are ASCII character representations of hex numerals which are bit-mapped. The first character of each string identifies which bit maps are in that string. For example, the "a-string" starts with a lower case "a" and identifies most of the basic modem capabilities such as modulation standards supported and support for AutoSync.Since the following tables identify features for Hayes modem products, the values included here and the number of strings are subject to change and expansion. The maximum length per string is 40 characters.The I4 text is displayed in the following form:     a097800C204C264     bF60410000     r1031111111010000     r3000111010000000surrounded by additional <CR> and <LF> characters as are required by the V command option in effect. According to convention, all <CR> and <LF> characters are defined by S3 and S4, respectively. The meanings of the a, b, r1, and r3 strings currently defined are described below.I4 "a" StringThe first string, the a-string, is composed of the ASCII character "a" followed by a series of hexadecimal characters (D1-D16 in this example). The bit map for each byte is defined below.a D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 D17 D18....------------------------------------------------------------------------D1, D2     ReservedD3         Bit 3: Indicates modem based on SM1200FE commands            Bit 2: Indicates modem based on SM2400 commands            Bit 1: Indicates that modem supports &J commands           Bit 0: Indicates that modem supports &L commands D4         Bit 3: Indicates that modem supports AutoSync (&Q4)D5         Bit 3: Plug-in board modem product           Bit 2: Standalone modem product           Bit 1: Supports &H0 through &H4           Bit 0: Supports &I0 through &I4 D6         Bit 3: Reserved           Bit 2: Supports M4 command           Bit 1: Supports 32-bit FCS (frame check sequence            for AutoSync)           Bit 0: Supports AutoSync IID7         Bit 3: Supports V.22 at 1200 bps (B0)           Bit 2: Supports 212A (B1)           Bit 1: Supports ASB in V.23 75 bps xmt/1200 bps rcv (B2)           Bit 0: Supports ASB in V.23 1200 bps xmt/75rcv (B3)D8         Bit 3: Supports V.23 1200 bps xmt/75 bps rcv (B4)           Bit 2: Supports V.23 1200 half duplex (B5)           Bit 1: Supports V.23 75 bps xmt/1200 bps rcv (B10)           Bit 0: Supports V.23 75 bps xmt/600 bps rcv  (B11)D9         Bit 3: Supports V.21 100/300 bps (B15)           Bit 2: Supports ASB in V.23 75 bps xmt/600 bps rcv (B20)           Bit 1: Supports ASB in V.23 600 bps xmt/75 bps rcv (B21)           Bit 0: Supports V.23 600 bps xmt/75 bps rcv  (B22)D10        Bit 3: Supports V.23 600 bps half-duplex (B23)           Bit 2: Supports V.22bis at 2400 bps (B30)           Bit 1: Supports V.27ter at 2400 bps (B31)           Bit 0: Supports V.27ter at 4800 bps  (B40)D11        Bit 3: Supports V.32 full duplex at 4800 bps (B41)           Bit 2: Supports Express 96 at 4800 bps (B42)           Bit 1: Reserved           Bit 0: Supports V.29 half duplex at 4800 bps (B44)D12        Bit 3: Supports V.29 half duplex at 7200 bps (B50)           Bit 2: Supports V.32 full duplex at 9600 bps (B60)           Bit 1: Supports Express 96 at 9600 bps (B61)           Bit 0: ReservedD13        Bit 3: Supports V.29 half duplex at 9600 bps (B63)           Bit 2: Supports 103 110/300 bps (B16)           Bit 1: Supports V.32bis (7200/12000/14400 bps)           Bit 0: Reserved------------------------------------------------------------------------------------------------------------------------------------------------D1, D2      ReservedD14         0: Reserved            1: Personal Modem 1200            2: Personal Modem 2400            3: Personal Modem 1200 Plus            4: Personal Modem 2400 Plus            5: Pocket EditionD15         Bit 3: Reserved            Bit 2: Supports $ dial modifier and NO DIALTONE result code.            Bit 1: Supports S95 Bit 5 for COMPRESSION: result code            Bit 0: Supports S95 Bit 4 for AUTOSTREAM: result code D16         Bit 3: Supports S95 Bit 3 PROTOCOL: result code            Bit 2: Supports S95 Bit 2 CARRIER result code            Bit 1: Supports S95 Bit 1 CONNECT/ARQ result code            Bit 0: Supports S95 Bit 0 CONNECT XXXX (for DCE rate) ------------------------------------------------------------------------I4 "b" StringThe second string, the b-string, is composed of the ASCII character "b" followed by a series of hexadecimal characters (D1-D9). The bit map for each character is defined as follows:b D1 D2 D3 D4 D5 D6 D7 D8 D9....------------------------------------------------------------------------D1          Bit 3: V.42 Alternate Protocol Supported            Bit 2: V.42 LAPM Protocol Supported            Bit 1: X.25 Protocol Supported            Bit 0: LAPB (Point-to-point error control) protocol supportedD2          Bit 3: Reserved (should be set to zero)            Bit 2 MNP (TM) Class 5 supported            Bit 1: V.42bis supported            Bit 0: Compression through the X.25 network supportedD3/D4       These combine to indicate the number of AutoStream             Type A channels which are supported. The formula             (D3*16 + D4) is used. Zero means AutoStream is not supportedD5          Bit 3: Reserved            Bit 2: Reserved            Bit 1: Adjustable startup (ASU) is supported            Bit 0: Negotiates adjustable startupD6          Bit 3: &K5 not supported            Bit 2: &K5 supported            Bit 1: Unidirectional flow control            Bit 0: S105 N104 parameter supported------------------------------------------------------------------------I4 "r1, r2" and "r3" stringsThese ID strings allow software to determine the available speeds that may be used to send AT commands. The r1-string contains a bit map that indicates at which DTE rates the autobaud process is supported.The presence of the r2-string in the I4 result infers that S87 is supported and is required for autobauding at the higher speeds. To autobaud at one of the speeds indicated in the r2-string requires that S87 be set to match that speed. The r3-string is issued if synchronous DTE speeds are supported. The map indicates which DTE rates are supported in synchronous modes. Each r-string begins with the lower case letter "r" and may be followed by as many as 39 additional characters, not counting <CR><LF>'s that will be used to separate them from other strings. Those 39 additional characters are limited to the ASCII-HEX alphabet 0-9 and A-F.After the two lead-in characters (i.e., r<n>), all subsequent characters contain the DTE rate maps. All maps have the same mapping for convenience to software. (Refer to the following chart.) Not all bit assignments are possible: for example, the split speeds have no meaning in the r3 synchronous map and are always filled with zeros.In r1, if the bit is filled with a 1, the corresponding DTE rate is supported for sending AT commands to the device. A zero indicates that DTE rate is not supported for AT commands.In the r3 map, the bits simply indicate which DTE rates are supported for synchronous operation on-line. This does not indicate, however, the supported rates for synchronous V.25bis commands.Split speeds if available are marked in the r1 string only when the appropriate B command option has been selected. Future expansion of these strings may include new speeds that are not in strict ascending order.DTE Rate Bit Map for r1, r2 and r3 StringsCharacter    Bit #       DTE Rate------------------------------------------------------------------------ 3:  1       bit 0       45.45 bps     2       bit 1       50     4       bit 2       75     8       bit 3       75/600 (xmt is 75, rcv is 600)  4:  1       bit 4       75/1200     2       bit 5       110     4       bit 6       134.5     8       bit 7       50 5:  1       bit 8       300     2       bit 9       450     4       bit 10      600     8       bit 11      600/75 6:  1       bit 12      1200     2       bit 13      1200/75     4       bit 14      1800     8       bit 15      2000 7:  1       bit 16      2400     2       bit 17      3000     4       bit 18      3600     8       bit 19      4200 8:  1       bit 20      4800     2       bit 21      5400     4       bit 22      6000     8       bit 23      6600 9:  1       bit 24      7200     2       bit 25      7800     4       bit 26      8400     8       bit 27      900010:  1       bit 28      9600     2       bit 29      12000     4       bit 30      14400     8       bit 31      1680011:  1       bit 32      19200     2       bit 33      21600     4       bit 34      24000     8       bit 35      2640012:  1       bit 36      28800     2       bit 37      31200     4       bit 38      33600     8       bit 39      3600013:  1       bit 40      38400     2       bit 41      43200     4       bit 42      48000     8       bit 43      5280014:  1       bit 44      56000     2       bit 45      57600     4       bit 46      62400     8       bit 47      6400015:  1       bit 48      67200     2       bit 49      72000