Digi vs. Moxa

Hi everybody.

I’m doing communications tests though Digi Connect ME, that has been set as TCP Server, also known as inverse telnet, an raw TCP.

On the PC side, i have build an application using Borland C++ 5.0 and Windows Architecture Sockets, same as samples included in Digi CD.

The matter is that i have compared data transference rate with other brand TCP/IP RS232 servers (Moxa DE-311M) and have detected a huge difference. Test were done by transiting an Intel formatted HEX file, after each line is transmitted from the PC to the device a Carriage Return character is answered by the device.

Elapsed time to transmit file, comparative table:

Digi Connect ME (9,600 baud) : 2min 37sec
Moxa DE-311 (9,600 baud) : 1min 02sec

Digi Connect ME (19,200 baud): 2min 13sec
Moxa DE-311 (19,200 baud): 0min 45sec

Digi Connect ME (38,400 baud): 2min 00sec
Moxa DE-311 (38,400 baud): 0min 22sec

In both, i’m working with the same dll communications using the BDS Protocol.
Digi Connect ME Ethernet port has been set to 100MB/S Full Duplex.
This doesn’t seem to have an explanation from my side, more over considering that Moxa DE-311 employs a 16 bit 80186 processor and less memory.
I would like to ask how to improve Digi Connect behaviour. So, at least i could match competitors rate.

Any suggest?.


The Digi Connect ME (ARM7) has a NS7520 CPU which is much slower compared to an 80186 processor. I has 32 bytes serial FIFO organized in chunks/lines of 4 or 8 bytes each. If bytes are not dropping in aligned to the lines/chunks the processor might not process 32 bytes per FIFO interrupt, but less down to 1 byte per interrupt.

To improve this, you might buffer your data at the sending/transmitting side and send it in chunks of 32 bytes, or at least in chunks of 16, 8 or 4 bytes, with a short inter-character delay after one chunk.

Assuming this is about the Connect ME running plug and play firmware (PnP), it is recommended to run the latest plug and play firmware you can find on Digis support web site.