USR Courier
RTS(4) is a handshaking signal that pairs with ClearToSend(5). Do you have a
MR (modem ready) and TR (terminal ready) light on the USR? If both LEDs are
ON, then any mutual handshaking needs should be satisfied. If TR is OFF, check
your dip switch settings — you may be dip-switched into looking for a
handshake that is not present. There is usually some way of setting any modem
to accept a "no handshake" condition as ok, such as when using only pins 2, 3,
and 7 (send, receive, and ground).
* RR 13134