Premise Lantronix.. RTS/CTS... RFC2217?

[doczaius]

Having trouble with an old Marantz receiver using the Lantronix trick & a serial2net server. Using the marantz driver + lantronix, or even a custom device with codes from the Marantz documentation does not work. 
 
The connection per Marantz documentation is as below which I have configured the serial2net server with.
 
9600/8databits/no parity/1stopbit/RTSCTS flow control
 
Here is the particularly odd thing, and maybe somewhere herein lies the answer --  I have been able to connect to the serial2net server using putty and send commands per spec.. ie "@1A0",0x0D (power) which is @1A0 in ASCII with a carriage return at the end and nothing happens... HOWEVER, if I type the command, hit return and then promptly manually disconnect the serial cable, the command works and the reciever powers off.   
 
Does this make the least bit of sense to anyone?
 

 

[gatchel]

Can you set up your connection to not use hardware or software flow control?

 

[doczaius]

I switched it to no flow control in ser2net and it would not sustain a connection.  I tried the same going directly into my windows PC with putty and it was a similar result, the Marantz actually kept reporting "Check RS232" intermittently.
 
I searched the web for hours to try and find anything relevant... eventually I came across a small app, terminal.exe that allows you to send data to the serial port and also manipulate RTS high/low which I used with some success.  My understanding, from the sporadic info I cobbled together, is that this reciever uses an old implementation of RTS/CTS, that works somewhat inverted from the modern standard.
 
 

From: http://www.tldp.org/HOWTO/Text-Terminal-HOWTO-11.html
 

Old RTS/CTS handshaking is different
What is confusing is that there is the original use of RTS where it means about the opposite of the previous explanation above. This original meaning is: I Request To Send to you. This request was intended to be sent from a terminal (or computer) to a modem which, if it decided to grant the request, would send back an asserted CTS from its CTS pin to the CTS pin of the computer: You are Cleared To Send to me. Note that in contrast to the modern RTS/CTS bi-directional flow control, this only protects the flow in one direction: from the computer (or terminal) to the modem.
For older terminals, RTS may have this meaning and goes high when the terminal has data to send out. The above use is a form of flow control since if the modem wants the computer to stop sending it drops CTS (connected to CTS at the computer) and the computer stops sending.

 
I haven't quite nailed it down but if I understand correctly

1. set RTS to HIGH,
2. wait for the reciever to report CTS HIGH
3. set RTS to low
4. transmit data

Then this process would invert to receive status back from the receiver... 
 
I guess the question now is, is there any way to interface with this old protocol using Premise, or am I going to have to write a driver?
 
 
 
Excerpts from the Marantz SR7300/OSE RS232 Spec PDF: