Depends what type of OS you're using.
In MS-DOS 6/7/8 [6.22 is last stand-alone DOS based OS from MS; MS-DOS 7.00, 7.10 + 8.00 are part of Windows 95, 98 + ME, respectively] it is possible to have blinking text, using an ANSI device driver [pre-loaded in memory from CONFIG.SYS or AUTOEXEC.BAT], like ANSI.SYS included with all MS-DOS 6/7/8 [Win95/98/ME] releases, or 3rd party ANSI.COM [free].
ANSI allows full spectrum of 16 VGA colors, blinking, layouts, custom prompts, etc... in real/native DOS mode [outside Windows GUI], but a lil more restricted (no blinking) under Win9x GUI DOS box/session/window.
But if you're using any WinNTx based OSes [NT4, 2000, XP, 2003, Vista, 2008 or 7], you're out of luck, because the DOS console is merely a virtual machine, not the "real" DOS mode.
And Microsoft disabled completely [mainly for security + compatibility reasons] the access to real mode hardware resources.
Therefore in NTx OSes there is no text blinking in DOS [DOS is available only as a window/session/box/console = VM (Virtual Machine)], nor keyboard shortcuts for that matter. And the ANSI functions are implicitly disabled [although the obsolete file ansi.sys is still found in %windir%\system32], since there is no "real" DOS mode.
EchoX uses same functions as DOS VM to display colors.
There might be a tiny possibility...
1. find a 3rd party NT-compatible DOS tool/device [?] which allows limited access to hardware resources in DOS VMs [console];
2. try to learn how to tweak MS PowerShell [free add-on in XP/2003/Vista/2008 and native in Win7]:
Tweaking PowerShell to display blinking text is probably a long shot, but I have no experience using it.
Basic/Qbasic also uses ANSI functions to change colors and blink. Therefore most of those functions will be disabled in NTx OSes.
Although I haven't tried runnig Qbasic programs from DOSBox [free GPL]: