Black Box MD1640A Modem User Manual


 
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SERIES II INTELLIGENT DATA/FAX MODEMS
User Guide for Series II Modems
The #V command gives the user the option of including V.32terbo as
part of the handshaking process in both Orignate and Answer modes.
Entering AT#V0&W0<CR> includes the V.32terbo mode in
handshaking. Entering AT#V1&W0<CR> disables the Series II Modem
336 from using V.32terbo mode in the handshaking process (default).
Async/Sync Mode Switching &M
This command can be used to set the on-line mode to either
synchronous or asynchronous. AT&M0 will set the Series II Modem to
Asynchronous mode, and all communications will be asynchronous in
both On-line and Command modes. AT&M1 causes the Modem to com-
municate asynchronously when in Command mode and switch to syn-
chronous mode while on-line. The modem defaults to &M0
(asynchronous communications) on reset or power-up.
Synchronous Transmit Clock Select &X
The &X command selects the Synchronous Transmit Clock Source in
conjunction with DIP-Switch #11. DIP-Switch #11 in the UP position
enables External clocking. DIP-Switch #11 in the DOWN position
enables Internal clocking (default position). External clocking is when
the DTE provides transmit clocking to the modem on pin 24 of the
RS232C interface.
&X0 is the default setting, which allows DIP-Switch #11 to control
Internal/External Clocking (default Internal). Internal clocking is
when the modem provides transmit clock to the DTE on pin 15 of the
RS-232C/V.24 interface. The &X1 command overrides DIP-Switch #11
and selects External clocking. If DIP-Switch #11 is UP (External
clocking), you can not override Internal clocking. &X2 enables Slave
Clocking. The &X2 Command causes the Series II Modem to generate
the transmit clock timing (pin 15) from the receive clock (pin 17) from
the DTE (therefore 15 and 17 are the same). In this mode (Slave
Clocking), all timing is controlled by the receive clock.