Depending on the permissions setup you might need to be root to run it (or use sudo) - I haven't really used it under OSX. Many downloads like Securecrt 3.3 may also include a crack, serial number, unlock code, cd key or keygen (key generator). If you do want to use something built in that does't do its own terminal emulation then there is the cu command. SecureCRT And SecureFX 8.3 (Mac OSX) 1: 2,448 KB/s: VanDyke SecureCRT And SecureFX 8.3.0 Build 1514: 1: 2,100 KB/s: SecureCRT And SecureFX.8.1.3 MacOSX: 1. Remember screen was built for use on dumb terminals where, I can assure you, it's the best thing since sliced bread but thats why it emulates its own terminal within your window. Screen also has copy and paste support built in but you don't need to use it if you are using a modern windowing system like OSX. Perhaps the easiest way to use it, assuming you are using the default key bindings, is CTRL-A ESC and then use your cursor keys to scroll around. With that out of the way I can say that screen does have a scroll back buffer.

If you are the only serial port user on your system it probably doesn't really matter if you use cu or tty but cu is the norm when your connecting out via serial (as opposed to waiting for something to connect in).

Securecrt mac serial