VT510 terminal not working

Hallo, i want to run a vt510 terminal at a sl-10.0 computer. I connected it with a serial port (cable and port are working, i used them for a modem before), and edited the /etc/inittab adding the following line: S1:12345:respawn:/sbin/agetty -L 9600 ttyS1 vt510 i tried all 4 ttySx i have, and also tried "vt100" as terminal with emulation on the vt510. I don't even get a login on the terminal. configuration of the terminal: word size: 8 bits parity: none stop bits: 1bit transmit & receive speed: 9600 baud transmit & receive flow control: XON/XOFF can anybody help me with the setup? thanks Paul