Hi, I am attempting to connect to multiple devices using direct serial lines. If I connect to one device at a time then I am able to communicate using a TCP/IP socket with that device. When I establish a second connection using a second serial line to another device then PPP is setup successfully but the socket connection fails. When I try to ping the devices I find that I can not reach either the first of the second device. If I now disconnect the first 'dial-up' connection I can now open a socket to the second device. Windows XP does not share this problem. If I go through the same scenario with XP I can successfully open sockets to both devices at the same time. The behaviour depends on the connections. Some connections appear to be independent. I can open 2 to 3 'independent' connections but and then hit the problem on the next connection. When this happens the last connection will cause one of the earlier connections to fail. Again both the last connection and its 'pair' will stop responding to a ping. When either of these 'dial-up' connections is disconnected its pair will work again. I can see no pattern in the IP addresses of the 'paired' connections. For example RAS connection with 192.168.245.141 will not work with RAS connection 192.168.245.116 but will work with the connection with IP address 192.168.245.113 I have looked at the properties of the connections and done ipconfig /all and can see no significant difference from XP. The only minor difference is that XP shows a standard physical address. The Windows 7 is PPP adapter PROACTIV on COM17: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : PROACTIV on COM17 Physical Address. . . . . . . . . : DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.245.141(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.255 Default Gateway . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Disabled For XP it is PPP adapter PROACTIV on COM17: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface Physical Address. . . . . . . . . : 00-53-45-00-00-00 DHCP Enabled. . . . . . . . . . . : No IP Address. . . . . . . . . . . . : 192.168.245.141 Subnet Mask . . . . . . . . . . . : 255.255.255.255 Default Gateway . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Disabled I would appreciate any help. Thanks Russel

Hi Russel, Regarding the issue, I suggest updating the serial ports driver and BIOS from manufacture's site. If the issue persists, you could set a manually-operated serial port switch box or serial port expander to check the result. Best Regards, Niki Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Niki, Thanks for the suggestion. However, the serial port is behaving fine. After further investigation the cause of the problem appears to be that Windows 7 is only adding half the entries to the routing table and in particular is omitting the route from the PPP adapter to the device at the other end of the link. I found that the PPP connections work if I manually run the command route add 192.168.245.nn 192.168.245.1nn where 192.168.245.nn is the IP of the device and 192.168.245.1nn is the IP of the PPP adapter This entry appears automatically in the routing table for XP when the connection is started but not for Windows 7. Regards Russell russell_ck

Hi, Please help me collect Route Table. Open commend prompt with elevated privileges, then type: route print ->C:\1.txt, upload the 1.txt to SkyDrive. Best Regards, Niki Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.