User guide

MS-DMT Guide v1.04

Released 05-30-2014

provide proper results. However the minimum configuration running the MS-DMT requires any

external terminal application running on a second PC via an RS-232 null connection.

However the use of an external terminal application on the same PC via VCP based

communications requires more processing power and RAM. A minimum system based on a

1.86Ghz Intel Pentium M or 1.66Ghz Intel Core 2 class processor with 2GB physical RAM will

support using the MS-DMT Data Port on the same system via a VCP connection for basic

external terminal applications.

One AC’97 compliant, 48khz, 16 bit minimum PC Sound Device that is dedicated to being the

radio modem physical layer device and not used as the Windows system sound device or by any

other application is required. It is preferred that the sound device be external to the PC for best

results.

One physical RS-232 port is required for uninterrupted radio push-to-talk (PTT) activated prior

to and during data transmission via either RS-232 DTR or RTS lines or CAT PTT.

NOTE: Optionally, an external hardware PTT based very fast VOX activated keying from the modem

waveform audio is permitted as long as it is uninterrupted during the data transmission. For example,

the DLY setting on the popular fast VOX PTT based Signalink USB must be at full CCW for absolute

minimum PTT delay. Radio only based VOX keying should NOT be utilized, but if you do so all delay

settings must be at their absolute minimum.

One physical RS-232 port is required for use of the MS-DMT Data Port if the external terminal

program is running on a second PC.

NOTE: External terminal programs running on the same PC require the use of a paired set of VCP ports

where the use of Com0Com for 32 or 64 bit computers is recommended. Use of the ‘enable overrun

buffer” is recommended. For Window 7 and later a signed version of com0com is required.

NOTE: MARS-ALE must not be subjected to power conservation saving settings and must never shut down

the hard drive and the OS must never go into system standby or hibernate modes and screen savers must

be disabled as well as wireless networking. Wired networking may be tolerable on some systems but

must be evaluated as to DPC latency.