Hi, In out project we need to send data between two modems. We are planning to use javax.comm APIs write data to the modem port. A couple of questions that cropped up: 1. What are the chances of data loss or corruption. 2. Where does PPP come into picture? Do we need to use the PPP protocol? 3. Are there any Java APIs implementing the protocol. TIA, Prakash.
Beaumont Muni
Greenhorn
Joined: Nov 29, 2001
Posts: 5
posted
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Hi I didn't think that you need PPP to communicate between two modem or serial devices. At least that's been my experience from the low level perspective and labs carried in college. Basically the registers on the USART (or whatever they are) needs to be initialized ie protocols, baud rates etc, need to be set. The devices (or modems should auto negotiate inspite of the baud rate set). The receiving end should also do the same to receive incoming data. PPP implements TCPIP protocol over serialm(utilizing two way communication (as opposed to SLIP or Serial IP), so the process of dialing the remote site is needed to initiate a request. Thus the remote end is dialed up initially to establish connections between the two modems. Once the two sides decide at what level they can communicate (through auto negotiation, authentication etc, tcpip can kick in after an ip address is allocated from a pool to the requesting modem, thus allowing http and other protocols to function. At least that is my understanding of how ppp works on the Unix OS. Recently a company I worked for did some serial io based projects using the serialio package ( had to be purchased from a vendor at www.serialio.com).
Prakash Prabhakar
Greenhorn
Joined: Nov 08, 2001
Posts: 8
posted
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Hi Beaumont, Thanks for your reply. I'd been out of office for some time and could not follow up the question I'd posted. A happy new year to you. Regards, Prakash
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