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PN 88300150
RTS. Refer to the &R command for control of Clear to Send functionality. The factory default
setting is &RF1.
&S
Data Set Ready Control
The &S command lets you control the status of the Data Set Ready signal (DSR - Pin 6) on
the RS232C interface. You have three choices. You can force the signal high, allow it to act
normally, or set it up so that it will stay high until the modem disconnects, go low
momentarily, and then go high again. The last option is useful with some CBX phone systems
and mainframe front ends, which require DSR to act in this manner.
To allow DSR to act normally, type AT&S1 (this is the factory default setting). To force DSR
on, type AT&S0. To set up DSR so that it drops for one second on disconnect and then
comes up again, type AT&S2. (If you want the drop time to be something other than one
second, use S-Register S24 to change this value. Refer to Chapter 4 instructions for S24.)
If you type the &S2 command, be sure that the DSR DIP-Switch on the modem circuit board
is set to allow DSR to act independently of Carrier Detect (CD). Refer to Chapter 7 for details.
&SF
DSR/CD Interaction Control
In typical applications, Data Set Ready (DSR) will follow Carrier Detect (CD). &SF0 enables
DSR to follow CD, and is the factory default setting. &SF1 enables DSR to operate indepent
of CD. If this is the case, refer to the &S command for control of Data Set Ready functionality.
3.9.4 Phone Line Conditioning Commands
#A
Auto Speed Detect
The #A command lets you select operation as either a 9600/4800 bps ITU-T V.32 standard
modem, a 2400 bps ITU-T V.22 bis (Bell 2400) standard modem, a ITU-T V.22/Bell 212A
(1200 bps) modem or a Bell 103/113 (300 bps) modem. The function of the #A command is
to detect and select the operational baud rates which the MT2834MR will use for initial
handshake and speed selection.
Note:
The #A command does not control the originating bps rate of the modem (that is done by the
Modem Baud Rate command $MBXXXX), but only answer mode fallback speeds.
Type AT#A0 (or AT#A) to cause the MT2834MR to operate starting at 28,800 bps with
fallback to 19,200 to 14,400 to 9600 to 4800 to 2400 to 1200 to 300 bps. AT#A1 uses 28,800
bps only. The AT#A2 causes the modem to operate at starting speeds of 28,800 bps, with
incremental fallback to 19,200, 14,400, 9600, and 4800 bps. The AT#A3 command causes
the modem to begin operation as a V.22bis modem at 2400 with fallback to 1200 to 300 bps.
AT#A1 is the factory default setting.
&L
Leased Line (2/4 wire, Answer/Originate) Mode Select
The &L command lets you select one of four modes of MT2834MR leased-line operation.
You can select any combination of 2- or 4-wire operation in Answer mode or Originate mode.
The factory default setting (on power up) is &L0 (dial-up mode operation).
Type AT&L1 to allow just one attempt at a leased line connection. Type AT&L2A for 2-wire
operation in Answer mode. Type AT&L4A for 4-wire Answer mode operation. Type AT&L2D
for 2-wire Originate mode operation. Type AT&L4D for 4-wire Originate mode operation.
Note:
You must include the A or the D command in the dialing string with the &L command.
The &L command is intended for use by the MultiCommManager administrator. MT2834MR
power must be cycled to clear the &L command. The &L command is not stored in modem
memory. DIP-Switch #10 in the UP position (Dial-Up Operation) overides the &L command
(refer to Chapter 7 of this manual).
4/3/01
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