Subject: Re: dec modem
To: Daniel Senderowicz <>
From: D. Sean Davidson <>
List: port-pmax
Date: 04/01/1997 15:09:48
Here are what the DIP switches are for the DF296:

To put these modems into AT mode use the command (ENABLE AT) from
DMCL command mode.  Then just use about any modem manual that has
the AT command set.

Put this in real fast so there may be some typos here and there.


SW1-* references are for the 8 dip switch
SW2-* references are for the 4 dip switch

Factory Defaults Enable (SW2-1)

This switch enables or disables factory default.  This switch
causes a return to DMCL with all parameters set to the factory
default value, regardless of whether the write command was used.
Also, callback and dial memory locations are cleared, as well as
any data in the callback status loggin area.  The access
password is reset to the "Undefined" state.  Return the factory
defaults switch to the disable position after use, to prevent
accidenttal factory defaulting.

User Defaults Enable (SW2-2)

This switch enables or disables user defaults switches.  When placed in
the ON position, the modem reads the swlections of SW1.  To change the
SW2 option from the default value, make the change to the appropriate
SW1 seitches first, then place the User Default Enable switch to ON and
cycle the power, or type "Enable Test" in DMCL, or enter the Z command
in the AT command language to reset the modem.

Remote Access Enable (SW2-3)

This swtich allows a Customer Service Engineer to dail the local modem
from a remote modem and examine or modify the local modem's operational

Callback Security Enable (SW2-4)

This switch enables the callback security feature.

User Default Switches

The following switchs are process only when the User Deafults Enable
switch (SW2-2) is enabled.

Command Interface (SW1-1, SW1-2)

These switches select asynchronous DMCL, asyncrhonous AT, asynchronous
Dumb, or syncrhonous DMCL mod eof operation.

When an asynchronous mode of operation is selected, SW2-4 and SW2-5
define the parity type.  When a synchronous mode of operation is
selected, SW2-4 and SW2-5 define the source of the synchronous clocks.
SW2-3 and SW2-6 are non-functional during the synchronous mode of

When Dumb mode is selected, the following will occur:

	1. DMCL command interface is selected.

	2. The modem will not respond to any DTE data received and will
	   not transmit data to the DTE while off-line.

	3. All DMCL parameters selected are stored previous to the
	   enabling of Dumb mode will remian operationl, that is, error
	   correction, speed buffering, callback memory, and so forth,
	   except those that would vilate item #2.

Dumb mod eis useful when the DECmodem V32 is to be used for an answer
only application.

Parity Enable (SW1-3)

This swtich enables or disables the parity feature in asynchronous data
format.  In syncrhonous dat aformat thsi swithc is non-functional.

Parity Type (SW1-4, SW1-5) (Async Data Format)

These switches select odd, even, mark, or space parity in asynchronous
data format.  In syncrhonous data format, these switches are

Synchronous Timing (SW1-4, SW1-5) (Sync Data Format)

These switches select the source of timing for syncrhonous data format
as follows:

	o Internal - The modem generates the transmit and receive clock
	  signals and applies the to TXCLK and RXCLK on the DTE

	o External - The local DTE sources the transmit clock signal on
	  the DTE interface EXTCLLK signal.  The modem applies the clock
	  to TXCLK on the DTE interface.  RXCLK is generated by the

	o Slave - The modem derives the transmit clock signal from the
	  incoming data carrier signal and applies it to TXCLK on the
	  DTE interface.  RXCLK is generated by the modem.

Number of Data Bits (SW1-6)

This switch selects either 7 or 8 data bits per character.  This applies
only when the modem is set to asynchronous data format.  In synchronous
data format, this switch is non-functional.

Modem Porotocol (SW1-7, SW1-8)

These switches select V.22, V.22bis, V.32 TCM (no fallback), V.32 TCB
(with fallback) in asynchronous or synchronous data formats.