RB450 and US Robotics 5686 modem

I’m trying to connect an external US Robotics 5686 modem to a RB450. I have the DB25 to DB9 pin adapter and the modem works correctly connected to my laptop successfully dialing out using windows and linux, also it responds correctly to various AT commands. I’ve disabled the console on port serial0 so it’s available to outgoing PPP and read the wiki article found here http://wiki.mikrotik.com/wiki/How_to_connect_your_office_network_with_Dial-up_Modem/Connectivity

I’m entering the username, password, port, and phone number for the ppp-client connection. When I try to connect it sticks at “reseting link…” I’ve also tried using another routerboard with the same results. Help anyone??

Edit:

I just tried connecting to the modem from the routerboard using the /system serial-terminal serial0 command. The difference I see with connecting it to the routerboard instead of my laptop is the TR (terminal ready) light on the modem does not stay on. I can still see send/receive lights on the modem flicker when I send a AT command, but it does not give a response when plugged into the routerboard. I’ve tried changing the baud rate to 115200 and 56000.

The problem was hardware flow control being enabled by default on the external modem. Here is a wiki article detailing how to put the 5686 modem into software flow control so it will work with a RouterBoard. http://wiki.mikrotik.com/wiki/Routerboard_and_US_Robotics_5686