Modem Control Codes 2

Extended Command Set

&Rn Received Data hardware (RTS) flow control

&R0 CTS tracks RTS

&R1 Ignore RTS—Default

&R2 Pass received data on RTS high; used Pass received data on RTS high Extended

Command Set

&Sn Data Set Ready (DSR) override

&S0 DSR override (always On—Default)

&S1 Modem controls DSR

&S2 Pulsed DSR; CTS follows CD

&S3 Pulsed DSR

&Tn Modem testing

&T0 End testing

&T1 Analog loopback

&T2 Reserved

&T3 Digital loopback

&T4 Grant remote digital loopback

&T5 Deny remote digital loopback

&T6 Initiate remote digital loopback

&T7 Remote digital loopback with self-test

&T8 Analog loopback with self-test

&W Write current settings to NVRAM

&Xn Synchronous timing source

&X0 Modem’s transmit clock—Default

&X1 Terminal equipment

&X2 Modem’s receiver clock

&Yn Break handling. Destructive breaks clear the buffer; expedited Breaks are sent immediately

to remote system

&Y0 Destructive, but don’t send break

&Y1 Destructive, expedited—Default

&Y2 Nondestructive, expedited

&Y3 Nondestructive, unexpedited

&Zn=L Store last-dialed phone number in NVRAM at position

&Zn=s Write phone number(s) to NVRAM at position n (0-3); 36 characters maximum

&Zn? Display phone number in NVRAM at position n (n=0-3)

%Rn Remote access to Rack Controller Unit (RCU)

%R0 Disabled

%R1 Enabled

%T Enable Touch-tone recognition

Modem S-Register Functions and Defaults

S0

disables Auto Answer, equivalent to DIP switch 5 Down

S1 Counts and stores number of rings from incoming call

S2 Define escape code character. Default = +

S3 Define ASCII carriage return

S4 Define ASCII line feed

S5 Define ASCII Backspace

S6 Number of seconds modem waits before dialing

S7 Number of seconds modem waits for a carrier

S8 Duration (sec) for pause (,) option in Dial command and pause between command reexecutions

for Repeat (>) command

S9 Duration (.1 sec units) of remote carrier signal before recognition

S10 Duration (.1 sec units) modem waits after loss of carrier before hanging up

S11 Duration and spacing (ms) of dialed touch-tones

S12 Guard time (in .02 sec units) for escape code sequence (+++)

S13 Bitmapped register:

1 Reset when DTR drops

2 Auto answer in originate mode

4 Disable result code pause

8 DS0 on DTR low-to-high

16 DS0 on power up, ATZ

32 Disable HST modulation

64 Disable MNP Level 3

128 Watchdog hardware reset

S15 Bitmapped register:

1 Disable high-frequency equalization

2 Disable online fallback

4 Force 300bps back channel

8 Set non-ARQ transmit buffer to 128 bytes

16 Disable MNP Level 4

32 Set Del as Backspace key

64 Unusual MNP incompatibility

128 Custom applications only

Bitmapped Register

1

2 Dial test

4 Test pattern

8 Initiate remote digital loopback

16 Reserved

32 Reserved

64 Reserved

128 Reserved

S18 &Tn Test timer, disabled when set to 0

S19 Set inactivity timer in minutes

S21 Length of Break, DCE to DTE, in 10ms units

S22 Define ASCII XON 17 17

S23 Define ASCII XOFF 19 19

Modem S-Register Functions and Defaults

S24

S25 Delay to DTR in 10ms units

S26 Duration (10ms units) of delay between RTS and CTS, synchronous mode

S27 Bitmapped register:

1 Enable V.21 modulation, 300bps

2 Enable unencoded V.32 modulation

4 Disable V.32 modulation

8 Disable 2100Hz answer tone

16 Disable MNP handshake

32 Disable V.42 Detect phase

64 Reserved

128 Unusual software incompatibility

S28 Duration (.1 sec units) of V.21/V.23 handshake delay

S32

0 Disabled

1 Go off hook in originate mode

2 Go off hook in answer mode

3 Redial last-dialed number

4 Dial number stored at position 0

5 Auto answer toggle On/Off

6 Reset modem

7 Initiate remote digital loopback

S34 Bitmapped register:

1 Disable V.32bis

2 Disable enhanced V.32 mode

4 Disable quick V.32 retrain

8 Enable V.23 modulation

16 Change MR LED to DSR

32 Enable MI/MIC

64 Reserved

128 Reserved

S38 Duration (sec) before disconnect when DTR drops during an ARQ call

ARQ = Automatic repeat request

ASCII = American Standard Code for Information Interchange

BPS = Bits per second

CCITT = Consultative Committee for International Telephone and Telegraph

CD = Carrier detect

CRC = Cyclic redundancy check

DCE = Data communications equipment

DTE = Data terminal equipment

EIA = Electronic Industries Association

HDLC = High-level data link control

HST = High-speed technology

Hz = Hertz

LAPM = Link access procedure for modems

MI/MIC = Mode indicate/Mode indicate common

MNP = Microcom networking protocol

NVRAM = Non-volatile memory

RAM = Random access memory

ROM = Read-only memory

SDLC = Synchronous Data Link Control

MR = Modem ready

LED = Light-emitting diode

DTR = Data terminal ready

CTS = Clear to send

RTS = Ready to send

DSR = Data set ready.Voice/Data switch options: 1Duration (20ms units) of pulsed DSR when modem is set to &S2 or &S3Analog loopbackNumber of rings before automatic answering when DIP switch 5 is UP. Default = 1. S0 = 0