Related Manuals for GDI SM2400
Summary of Contents for GDI SM2400
- Page 1 MODEL SM2400 2400 BAUD DIAL-UP MODEM SMART MODEM USER GUIDE 280 Interstate 80 West Exit 1 / PO Box 1330, Verdi NV 89439 Phone: 775-345-8000 Fax: 775-345-8010 E-mail: traffi@sgdi.net...
- Page 2 PROPRIETARY DATA This document contains confidential, proprietary data with all rights and titles reserved by GDI Communications LLC. By accepting this document, the recipient assumes custody hereof and agrees not to disclose this data or any portion of this data to any unauthorized person without the prior written consent of GDI Communications LLC.
- Page 3 & reception, auto-dial/-answer/-speed detect, and Hayes command set compatibility, all on a single board with the standard Model 400 form factor. In addition to all of the features normally found in a Hayes-compatible modem, the GDI Model SM2400 is fully temperature tested.
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Page 4: Table Of Contents
TABLE OF CONTENTS PAGE GENERAL CHARACTERISTICS ………………………………………………… 3 INSTALLATION ……………………………………………………………………6 SHIPPING CONFIGURATION…………………………………………………… 7 ADJUSTMENTS…………………………………………………………………… 7 THEORY OF OPERATION ……………………………………………………… 8 System Description ………………………………………………………… 8 Description of Circuit Operation…………………………………………… 9 MAINTENANCE………………………………………………………………… 10 Preventive Maintenance…………………………………………………... 10 Alignments………………………………………………………………… 10 Trouble Analysis…………………………………………………………... 10 Special Considerations…………………………………………………….. 10 Waveforms and Voltage Measurements……………………………………... -
Page 5: General Characteristics
General Characteristics INDICATORS TXD Transmitted Data RXD Received Data Off Hook, on when modem is off hook DTR Terminal Ready, on when host is ready High Speed, on when in 2400 baud mode DCD Carrier Detected Originate/Answer mode, on when in answer mode OPERATING TEMPERATURE RANGE -30°C to +70°C HUMIDITY... - Page 6 TRANSMIT CARRIER FREQUENCIES V.22 bis: V.22: 212A: ORIGINATE 1200 Hz +/- 0.01% ANSWER 2400 Hz +/- 0.01% V.21 @ 300 bps: ORIGINATE ‘ space’ 1180 Hz +/- 0.01% ORIGINATE ‘ mark’ 980 Hz +/- 0.01% ANSWER ‘ space’ 1850 Hz +/- 0.01% ANSWER ‘...
- Page 7 GUARD TONES Guard tones of 1800 Hz or 550 Hz may is transmitted by the answering modem, for echo suppression. Default - no guard tone. Guard tone will not be transmitted in Bell 212A or 103 modes. COMMAND BUFFER SIZE 40 Characters maximum, which includes the required carriage return.
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Page 8: Installation
To/From RJ11C jack INSTALLATION Before installing the Model SM2400, it is necessary to determine if the controller application software expects to talk to the Smart Modem via ACIA1 (modem slot and C2) or ACIA2 (C20 only). If the software communicates with the smart modem via ACIA1, installation consists of simply plugging the modem into the modem slot and connecting the phone line to the modular jack (LINE). -
Page 9: Shipping Configuration
Command Set section. Switches The GDI Model SM2400 has an eight position DIP switch (SW1) that is used to 'strap' operating parameters. Only positions 1 through 6 are used. The following is a description of their function. -
Page 10: Theory Of Operation
The Model SM2400 solves this problem by essentially ignoring DTR (See Configuration Command &D). The factory default for DSR is always on (See &S). Since DSR is not monitored by the 170, this only becomes an issue when the Model SM2400 is connected to Data Terminal Equipment. -
Page 11: Description Of Circuit Operation
The power supply section is where all voltages necessary for operation of the modem are derived. The voltages required on the Model SM2400 board are +12, -12, +5, & -5 volts. The +/- 12 volts is obtained via the edge connector of the Model SM2400. VR1 regulates the +12 volts to produce a regulated +5 volts. -
Page 12: Maintenance
This modem is self aligning using a technique called adaptive equalization. Trouble Analysis The G.D.I. Model SM2400 is fully tested over temperature prior to shipment, however, rare circuit failures do occur for a variety of reasons. A Troubleshooting Flowchart and a written Test Procedure are included to aid in fault isolation. -
Page 13: Test Procedure
TEST PROCEDURE The following test procedure is outlined as a minimum effort to ensure correct modem operation. It relies on a diagnostic capability of the modem called analog loopback in which the modem communicates with itself. More thorough testing requires highly specialized equipment and is beyond the scope of this document. -
Page 14: Command Set
COMMAND SET The call set-up and user option commands for the Model SM2400 are designed to be compatible with the Hayes Smartmodem 2400. The following paragraphs explain the functional groups and the function of each of the user options. One configuration option is assigned a switch setting and is referred to as an 'adjustment'. - Page 15 (A/) Repeat Command AT does not precede this command. The repeat command instructs the modem to repeat the execution of the last command line stored in the command buffer. The repeat command can be used to redial a number if busy. This command is neither followed by carriage return, nor preceded by the attention command AT.
- Page 16 The H1 command will cause the telephone line relay to go off-hook. (In) Request Product Code and Checksum The I command requests the product code. The Model SM2400 will respond with 24x where x is the software revision level. The command Ii will cause a checksum to be computed on the internal ROM and returned as three ASCII numeric characters followed by a carriage return, line feed.
- Page 17 (Mn) Monitor On/Off speaker is off MO speaker is off speaker is off while receiving carrier (default) speaker always on speaker disabled while dialing or receiving carrier (On) On-Line The 0 command is used to return the modem to the on-line mode, after temporarily bringing it to the command mode by using the escape code (+++).
- Page 18 Result Codes Returned by Modem Meaning Short Form Long Form Command Line Executed Without Errors Connected at 300 bps CONNECT Local Telephone Line Ringing RING Carrier Lost or Never Received NO CARRIER Error in Command Line ERROR Invalid Command Line Line Length Exceeds Buffer Size Invalid Character Format Connected at 1200 bps...
- Page 19 (Xn) Enable Extended Result Code Forms of this command can have an effect on Long Form CONNECT messages, Dialing (Blind or Wait for Dial Tone), and BUSY detection. 'Blind' dialing means that the modem goes off-hook and waits a time period specified by register S6 before dialing regardless of the presence or absence of dialtone.
- Page 20 (+++) The Escape Code The escape code returns the modem to the command state from the online state, without releasing the telephone line. This command consists of an escape guard time (S12 default 1 second) and an escape character (ASCII code in S2 default '+'). The escape character must be issued three consecutive times with a guard time before and after the characters.
- Page 21 (&F) Fetch Factory Configuration Profile Configures modem with defaults contained in ROM. This is the easiest way to reconfigure the modem into a known state. This command does not modify NVRAM (see &Wn). The following is a list of conditions following the &F command. 2400 baud communications rate Bell 212A Even parity Auto answer disabled...
- Page 22 (&Mn) Async/Sync Mode Selection &M or &MO (default) selects asynchronous mode. The &Mi, &M2, and &M3 commands are reserved for future synchronous mode implementations. They will cause an ERROR response from the modem but will not affect operation. (&Pn) Make/Break Pulse Dial Ratio The make/break ratio for &P or &PO is 39% make and 61% break, U.S.
- Page 23 The command &T3 will initiate a Local Digital Loopback. This allows data being sent from the remote modem to be looped back, in the digital section of the local modem, and sent back to the remote modem. This mode allows the remote modem to run a remote digital loopback test.
- Page 24 The command &T7 starts a Remote Digital Loopback with Self-Test in accordance with CCITT Recommendation V.54. During the test phase, an internally generated data pattern of alternating ones and zeros at the selected bit rate is applied to the scrambler. An error detector capable of identifying errors is connected to the output of the descrambler.
- Page 25 (&Zn=string) Store Telephone Number The &Zn=string command is used to store one of four (n=0,1,2,3) telephone numbers (into NVRAM) for dialing at a later time using the DS=n dial stored number command. 'String' represents an ASCII string composed of dial digits plus optional modifiers. Dial digits may include 0 - 9 (pulse or tone dial) and A,B,C,D,#,and * (tone only).
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Page 26: Configuration (S) Registers
CONFIGURATION (S) REGISTERS The Model SM2400 incorporates 8 bit storage elements called S Registers. These registers contain information that control modem operating parameters. Some registers are associated with particular functions while others have groups of bits assigned to different functions. A subset of these registers may be stored in NVRAM (see &Wn). Rather than stepping through many discrete commands, the user may find it easier to modify modem operating parameters by writing directly to S Registers. -
Page 27: Back Space Character
S5 - Backspace Character This register holds the backspace character. When the modem receives the character defined by this register, it performs these four steps: 1. Echo the backspace character. 2. Sends an ASCII space. 3. Sends the backspace character a second time. 4. Deletes the last character in the command buffer. -
Page 28: Escape Code Guard Time
present. Allowable values are 1 to 255. Any loss of carrier will result in a disconnect if register S10 is smaller than S9. The actual length of loss of carrier is the delta between S10 and S9. Default value: 1.4 seconds S11 - DTMF Duration and Spacing Register Sil allows for adjustable tone-dialing duration and spacing. - Page 29 S15 - Not Used S16 - Modem Test Options 7 6 5 4 3 2 1 0 0 Local Analog Loop Disabled (Default) 1 Local Analog Loop Enabled (See &T1 command) Not Used 0 Local Digital Loop Disabled (Default) 1 Local Digital Loop Enabled (See &T3 command) 0 Loopback Off (Default) 1 Loopback On (Remotely Initiated)
- Page 30 S21 - Bit Mapped Options 7 6 5 4 3 2 1 0 Not Used Not Used 0 CTS follows RTS (Default) (See &R command) BIT4/BIT3 (See &Dn command) 0/0 Modem Ignores DTR 0/1 Command State ON to OFF DTR 1/0 Hangs Up ON to OFF DTR (default) 1/1 Initialize...
- Page 31 S23 - Bit Mapped Options 7 6 5 4 3 2 1 0 0 Ignore Remote Loopback Request 1 Accept Remote Loopback Request (Default) (See &T4 and &T5 commands) BIT2/BIT1 Baud Rate (See AT command) 0/0 0 to 300 bps 0/1 invalid 1/0 1200 bps 1/1 2400 bps...
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Page 32: Programmable Options Not Saved In Nvram
S27 - Bit Mapped Options 7 6 5 4 3 2 1 0 BIT1/BITO (See &M command) 0/0 Asynchronous (Default) 0 Dialup Line (Default) 1 Leased Line (See &L command) Not Used BIT5/BIT4 Reserved to define future synchronous mode timing source 0 CCITT V.22 BIS/V.22 1 BELL 212A (Default) (See B command) -
Page 33: Command Summary
COMMAND SUMMARY - Defines baud rate and precedes command line - Re-executes last commandA - Modem goes off-hook in answer mode - Sets CCITT V.22 operation when at 1200 bps - Sets Bell 212A operation when at 1200 bps Dstr - Dial string following D in command line - Modem does not echo commands - Modem echoes commands back to terminal... - Page 34 &C - DCD always ON &C1 - DCD ON if carrier present &D - Modem ignores DTR &D1 - Assume command state (ON to OFF DTR) &D2 - Command state,hang up,disable Auto-Answer (ON to OFF DTR) &D3 - Initialize (ON to OFF DTR) &F - Load factory configuration profile &G...