User guide

MS-DMT Guide v1.04
Released 05-30-2014
118
An option when the system resources are too low or DPC latency is too high on the same PC to
support both the MS-DMT and external terminal or when the DMS-DMT is running under
another operating from the external terminal application, real physical serial ports can be used
along with a Null Modem. It is not recommended to use real serial ports on the same PC running
both applications as the effects of RS-232 interrupts has on DPC latency. The selected port
parameters much match between the MD-DMT and external software when using physical serial
ports.
NOTE: With the trend of no physical hardware serial ports and the need to use device driven RS-232
adapters, another option would be to dedicate an older PC up to the task to MS-DMT and make use of
com0com and the com2tcp tool to tie MS-DMT to a com0com virtual serial port and then to com2tcp
and via the PC’s wired ethernet port to the home TCP/IP network to connect with a second machine
running the external terminal application.
The MS-DMT Data Port is always opened in binary mode to support ASCII characters 0-255 as
the modem itself will support passing binary range characters, however, at present the internal
incoming data display will only display the normal printable range ASCII characters. In that
regard, when “TRANS” in use by the sending station to transmit binary data, when SYNC_EOM
is used, the monitoring of the non-ASCII can be achieved if “HEX Eng. View” is checked. However
the intercept of content that contains a Null (0x00) character while just SYNC will cause a
modem receiver will reset. The use of ASYNC_EOM will result in gibberish.
The Data Port follows the selection of ASYNC_EOM, SYNC_EOM and SYNC modes available for
selection to process the data port data stream as ASCII range (decimal 20 through 128)
characters. However, when “TRANS” is checked, the mode will be locked into a compatible SYNC
with EOM mode coded to support passing a binary data stream, be it Binary, mixed Binary/ASCII
or just ASCII.
If “RoN” which stands for “Reset on Null”, is checked in addition to “TRANS”, then in addition to
resetting on the EOM, the modem will reset on “Null”, this provides for modem reset in case the
EOM is corrupted, missed or not sent. However, RoN can not be used if any binary data is being
sent that contains even one ASCII value 0x00 Null character or else the null character in the
message will prematurely cause a modem reset.
When the data port is active, all data received is still displayed and treated the same within the
MS-DMT application to include RX logging except when “TRANS” is checked. All data sent and
received via the data port passes through MS-DMT application when the data port is active with
no MS-DMT parameters selected effecting the sending of data or the display of received data via
the 3rd party application. The most recent message sent via the 3rd party application is retained