Serial Port Flow Control \Q | Black Box 3600 MODEM guide

Protocols

Serial Port Flow Control \Q

The \Q commands set the type of flow control used by the serial port. If the serial port speed exceeds that of the modem connection, characters may be sent by the DTE to the modem faster than it can send them to the remote modem. The modem holds characters in an internal buffer until they can be transmitted. When this buffer is full, the modem uses flow control to stop data from the DTE. As the modem continues to transmit data and the buffer empties, flow control is again used to cause the DTE to resume sending data.

•The \Q - \Q3 commands affect both DTE and DCE flow control.

•The \Q4 - \Q7 commands affect only flow control by the DCE.

•The \Q command disables flow control bilaterally.

When the \Q1 command is used, the modem generates and accepts XON/XOFF characters to start and stop the data flow. These characters have the same parity as the DTE setup taken from the last AT command.

When the \Q2 command is used, the modem uses CTS off to stop the data from the DTE and CTS on to restart it.

When the \Q3 command is used, the modem uses CTS off to stop the data from the DTE and CTS on to restart it. The DTE uses RTS off to stop data from the modem and RTS on to restart it.

The \Q4 command disables flow control by the DCE.

The \Q5 command enables XON/XOFF flow control by the DCE only.

The \Q6 and \Q7 commands force the modem to use RTS off to stop data from the modem and RTS on to restart it. This does not affect DTE flow control.

Command	Operation

\Q	Disable bilateral flow control

\Q1	Enable bilateral XON/XOFF flow control

\Q2	Enable DTE CTS flow control, disable DCE flow
	control

\Q3	Enable CTS/RTS bilateral flow control

\Q4	Disable DCE flow control

Modem 3600

6-7

Image 109

$Black Box 3600 MODEM manual Serial Port Flow Control \Q$

Contents

3600 Trademarks $2334253/426 #$%&*+ #$%&,+ $$$ $$$$ $&% $$% $%%-% $&% % %&$ $ !+ #**# # 3! #41% #**# # 3! #41%&, +2 #4!# 3C $ 35 F + *&*A1 $ @ $A = 01BB Page $%% $ +,-*./0 1 **-*2**,3/0 Page Page Page Page #26 Page Page Page 555,5,65E##E%E% % Page #5 S7-# Shelf-Mount Units Chapter Introduction Data Mode Features Software Fax ModeCommunications Software Class 1 Fax Communications Software Internet Browser Functional DescriptionPhysical Rear Panel 115 Vac Model Card Version of the Modem Modem 3600 Card Mounting Accessories Chapter Installation AC Power Connection Electrical InstallationDC Power Connection DTE Connection Digital Interface Signals Pin 232D Signal Description Pin Signal Description s DCE Pin Signal Descriptions Telephone Line Connection Dial-up Connection 115 Vac Model Dial Mode Pstn Connection Dial jack Leased Line Connection TELSET/LEASED Line Jack Leased Line Connection 115 Vac Model MD1000C Connections Shelf-Mount MD1000C Installation Chapter Getting Started Power-UpOption Selection Placing a Call Autodialing from a Terminal with the AT CommandsDialing with a Standard Telephone Autodialing from Front Panel Ending a Call Answering a Call Reasons for Call Terminatio n Condition Reasons for Call Termination Reasons for Call Termination Condition Page LED Descriptions Chapter Front Panel Operation LCD Menu Operation LCD Menus Reg LCD Menu Option Selectio n Main Menu Submenu Submenu Item Option Com Reg LCD Menu Option Selection Submenu Main Menu Option Com Reg Lease line only † Dial line only Modify Change DTE Speed DTE=DCE Modify Change DTE Dial Method Async Modify Change DTE RTS/CTS Delay Password of 0000 disables front panel security Front Panel Security Front Panel Operation Command Categories Chapter AT CommandsOperation Modes Offline Command Mode Sending Commands to the ModemOnline Command Mode Autobaud Guidelines for Creating Command Statements Creating a Command Statement AT Repeating a Command a Command Statement BufferMonitor Display Backspace Key Numbered Commands Response CommandsGroup Commands Digit / Word Selection Command OperationResponse Displays Q Negotiation Displays W Call Progress / Connect Speed Messages Number Code Application *RC Command Code Set Number Operation Code Message Meaning Response Number Codes / Messages DTE rate 31200 bps Connect 300/V42 Connect 300/MNP5 Dialing D Dial Commands Pulse Dialing P Tone Dialing TInsert Long Pause Wait for Second Dial Tone W Remaining in Command Mode Switching to Answer Mode after Dialing RHook Flash Wait for 5 Seconds of Silence @ Dialing a Stored Telephone Number Sn Switching from Voice to DataAutodial Number Location *AUn Voice Calls Manual Answer AT Command Answer aAutoanswer S0 Caller ID *ID Caller ID Message s Modem sends this message Distinctive Ring *DR Data Carrier Detect &C Terminal Interface Commands Data Terminal Ready &D Data Set Ready &S Request to Send / Clear to Send &R Serial Port Ring Indicator Pin 22 \R Changing from Data Mode to Command Mode +++ General CommandsDTE Controlled Fallback Rate Pin 23 *FB Local Character Echo E Hanging Up H, H1 Online Character Echo FFast Disconnect H2, H3 Eprom Check Speaker Volume LSpeaker Control M Return Online O Asynchronous / Synchronous Mode Selection &MLong Space Disconnect Y Bis Guard Tones &G Make / Break Dial Pulse Ratio &P Rate Selection Thresholds *TH Synchronous Transmit Clock Source &XAsymmetric Bit Rates *AS Modulation *MM Maximum DCE Speed %B Minimum DCE Speed %L Automatic Rate Adaption %R Auto Retrain %E Product Revision Level %V Manual Rate Adaption *RR Product Serial Number $V Online Quick Reference $HTalk / Data *DA Fast Train *FT Wire Operation Disable AT Command Set *NTPrivate Line Operation Dial Line Transmit Level *TDn Wire Dial-up Operation Wire Leased Line Operation Dial Backup Return to Leased Line from Dial Backup *LB Dial Backup *DBManual Dial Backup *LD Dial / Leased Line &L Configuration Profiles Configuration CommandsActive Profile Stored Profile Powerup Option Set &Y Storing a Configuration &W Load Factory Options &Fn Reset to Stored Configuration Z Storing a Telephone Command Line &Zx=n, *CNx,n, *ND View Configuration Profiles/Received Signal Options &V Soft Download Password %P1, $Y Remote ConfigurationRetaining / Restoring Options *RO Remote Security Code %P= Remote Configuration Security Enabling/Disabling Remote Configuration *RA Entering Remote Configuration %T=, &T Remote Configuration Format *RF Remote Configuration DTE Speed *RB Remote Configuration Saving or Discarding Options *RQ Page Reliable Mode Ccitt V.42 bis Error Control ProtocolChapter Protocols Normal Mode Auto-Reliable ModeConstant Speed Interface Data Compression Protocol Commands Direct ModeFlow Control Disconnect Buffer Delay %D Serial Port DTE Constant Speed \J Optional Detection Phase \M Auto-Reliable Fallback Character %An Operating Mode \N Serial Port Flow Control \Q Data Link Flow Control \G XON/XOFF Pass Through \X Break Control \Kn Inactivity Timer \T Transmit Break / Set Break Length \B Maximum Reliable Block Size \ASet Auto-Reliable Buffer \C 42bis Data Compression %C Diagnostic Test s Offline Online Chapter Test Mode OperationTest Categories Terminating a Test in Progress &T Test Commands Operation Local Analog Loopback &T1 Testing the Local Modem Local Analog with Test Pattern Local Analog Loopback with Self Test &T8 Local Digital Loopback &T3 Testing the Remote Modem Remote Digital Loopback &T6 Grant/Deny RDL Request &T4, &T5 Test Pattern %T Remote Digital Loopback with Self Test &T7 DTE Controlled Local Analog Loopback Pin 18 *LA DTE Controlled Remote Digital Loopback Pin 21 *RD Autocallback Security Chapter Security Operating without Low Security Low Security OperationOperating with Low Security Remote Operation Passwords Low Security CommandsLocal Operation LCD Indication of Security High Security Security Levels Superuser Default Passwords High Security CommandsEnabling High Security $EH=pw Disabling High Security $D Set Security Levels $Ln=m Setting Passwords $Pn=pw$pwSet User Callback Number $Cn=m Display Extended Feature Status $W? Extended Features $WDisplay / Reset Illegal Access Attempt Counters $M, $Mn, $M Removing a User $Rn Factory Reset $F=pw$pwSecurity Status $E? Display User Status $S? Local Logoff Command $$ Local Logon Command $n=pwRemote Logon Procedure $n=pw Verify User Information $In, $IBn Security Fax Operation Chapter Fax Operation Modem Initialization Fax DefaultsFax Autoanswer Class 1 Details Fax Associated OptionsStored Fax Profile Dial Command D Class 1 Commands On Hook H Answer Command a Service Class Capabilities +FCLASS=? Service Class Indication +FCLASS?Off Hook H1 Class 0 Operation +FCLASS=0 Fax Transmit and Receive Modes Receive Silence +FRS=TimeValues for Fax Modulatio n Modulation Speed Facsimile Receive +FRM=Mod Facsimile Transmit +FTM=ModValues for Fax Modulation Speed Hdlc Receive +FRH=Mod Hdlc Transmit +FTH=ModTest Supported Range of Values +FTx=?, +FRx=? Command Description Class 1 Result Code +FCERRORBinary File Transfer Fax Autoanswer +FAA= Registers Chapter Status Registers Changing S-Register Values Changing Register Values Sn=v, Sn=v Register Operation Sn?, Sn? Ring Count S1 Individual Bit Command Sn . # =v End-of-Line Character S3 Escape Character S2Line-Feed Character S4 Backspace Character S5 Carrier Detect Time S9 Pause Interval for Comma S8Lost Carrier Detect Time S10 Dtmf Tone Duration S11 S13 Bit Value Command DescriptionBit Mapped S14 S15 System Tests S16 Test Timeout S18S17 S19 Comman Bit Value Description Bit Mapped S21 Bit Mapped S23 Bit Mapped S22S24 Lookback Timer S28 RTS/CTS Delay S26DTR State Recognition S25 Bit Mapped S27 Bit Mapped S29 Bit Value CommandBit Mapped S30 S31 Remote Configuration Escape Character S41 DTR / Dial Backup Number to Dial S35Bit Mapped S32 S33 S43 Remote Configuration Guard Time S42XON Character from DTE S44 Xoff Character from DTE S45 Automatic Rate Adaption Threshold S53 Leased Line Transmit Level S52 Disable modem port flow control \Q3 Enable bilateral CTS/RTS flow controlFlow Control S54 S55 Compression Control S56 Inactivity Timer S58Bit Mapped S57 101 \K5 Break option Break Control S59 MNP compression enabled Enable auto retrainDisable auto-reliable data buffer Bit Mapped S60 Maximum Transmit Block Size S63 Disconnect Buffer Delay S62Auto-Reliable Fallback Character S64 S65-66 S68 Link Speed Status S67 10010 B18 33,600 bps DCE Independent Speed S69 Operating Mode Status S71 Operating Mode S70\M1 Enable V.42 fast detect 111 \N7 Lapm or MNP or native auto Reliable Callback Delay S74 Password Timeout S73Bit Mapped S72 Callback Retry S75 Autocallback Timer S78 Callback Retry Delay S76Lockout Threshold S77 Break Length S79 Serial Port or DTE Speed S80 Enable negotiation status 00001 DisabledMinimum DCE Speed S81 Negotiation Status S82 Bit Mapped S84 Enable any key abortS85-S87 Modulation Type S88 S92 S94 Current Modulation S91 Asymmetric Settings S96 Settings S95Bit Mapped S97 S98- S100 Chapter Bis Autodialer Software Guidelines Autodialer Command Strings and Parameters Invalid Responses Dial Parameters Bis Commands and ResponsesParameters Function Program Number Command PRN ann...n Dial Command CRN nn...n Dial Stored Number CRS a Intermediate Call Progress ResponseCNX@nnnnnBPS Sepacall progress messages Disregard Incoming Call DIC Request List of Stored Numbers RLNEtbsysystxLSNsp LSNann...nsepann...n Redial Last Number CRR n Connect Incoming Call CICLink Number by Address PRL ab Seprcall progress messages Request List of Linked Numbers RLL Request List of Version RLV Modem Options Command PRO xxxyy00EtbspspstxLSLsp LSLalsepal Modem 11-11 Restore Factory Settings PRP n Save Current Settings PRK Request List of Stored Options RLO xxx yy Options V.25 Autodialer Options Definition Settings Default Modem 11-15 Ebcdic Ascii Modem 11-17 Test Bilateral Commanded Loop Fuse Replacement Chapter MaintenanceMaintenance General Calling Technical Support Size Appendix a Specifications Modulation Speed Modem Data Rates Carrier Detect Level Page Pin Function Appendix B Phone Jack DescriptionsPage Jumper Option Selection Appendix C Hardware Options Figure C-1. Cover Removal Figure C-2. Jumper Location for Ground Option Replacing the Cover Fault Isolation Procedure Appendix D Fault Isolation Procedure Part Modem and Telephone Line Check Modem Page Command Reg Description Appendix E Command Index and Defaults Wait for 2nd dial tone S7 value Command Reg Description Restore factory configuration 1 † EBCDIC, NRZ1 Command Reg Description Command Reg Description Command Reg Description BER Command Reg Description DCE Switches modem to talk mode † Command Reg Description Command Reg Description Command Description Fax Command Description ValueModulationSpeed High Security Command Description Low Security †cannot be executed from remote configuration mode Modem Remote Configuration Commands Data bits, mark parity, 1 stop bit Reg Function Factory Set Default RO=Read only RW=Read or write Modem Default Synchronous Description Command Bis Dialer Commands Synchronous Description Command Response Message Meaning Response Messages INC Modem Options DCE rate 33600 Modulation automode Asynchronous Dial-up with V.42 bis Protocol AT&F or AT&F1Dial Line Options Tone dial Asynchronous Dial-up without V.42 bis Protocol AT&F2 Factory Option Set # Factory Option Set #3 Modem Options DCE rate Synchronous 4-wire Leased Line AT&F4 Factory Option Set #5 Asynchronous 4-wire Leased Line withV.42bis Protocol AT&F5 Factory Option Set # Synchronous 2-wire Leased Line Normal Originate AT&F7 Synchronous 2-wire Leased Line Forced Answer AT&F8 Synchronous V.25bis Dialer AT&F9 Factory Option Set #9 Appendix F Ascii and Ebcdic Characters NUL ESC ET end of transmission ACK0 DEL Hardware Options Hardware Options Hardware Options Hardware Options Appendix G Abbreviations and Acronyms Abbreviations and Acronyms PBX Xmit What You Need Appendix H Flash Upgrade Troubleshooting Service and Support Page Index Index-2V.3600 3600Index-3 Index-4V.3600 3600Index-5 Index-6V.3600 3600Index-7 Index Index-8V.3600