diff --git a/README.md b/README.md
index e59140c9..f9fcb447 100644
--- a/README.md
+++ b/README.md
@@ -237,7 +237,7 @@ A list of [known ITS machines](doc/machines.md).
    - TMPKIL, clean out old files in .TEMP.;.
    - TTLOC, Advertises physical location of logged in users.
    - TTY, displays TTYs with UNAME/JNAME/CORE and other info.
-   - TTYSWP, swap TTYs (binary only).
+   - TTYSWP, swap TTYs.
    - TYPE8, type 8-bit file.
    - UFIND, find users.
    - UNTALK, split-screen comm-link program.
diff --git a/bin/sys/ts.ttyswp b/bin/sys/ts.ttyswp
deleted file mode 100755
index 135e516b..00000000
Binary files a/bin/sys/ts.ttyswp and /dev/null differ
diff --git a/build/build.tcl b/build/build.tcl
index 406d35e8..feca3919 100644
--- a/build/build.tcl
+++ b/build/build.tcl
@@ -1145,6 +1145,10 @@ expect ":KILL"
 respond "*" ":midas sys1;ts os_sysen2;os\r"
 expect ":KILL"
 
+# ttyswp
+respond "*" ":midas sys;ts ttyswp_sysen3;ttyswp\r"
+expect ":KILL"
+
 # argus
 respond "*" ":midas sys2;ts argus_sysen2;argus\r"
 expect ":KILL"
diff --git a/src/sysen3/ttyswp.1 b/src/sysen3/ttyswp.1
deleted file mode 100644
index 653232a4..00000000
--- a/src/sysen3/ttyswp.1
+++ /dev/null
@@ -1,188 +0,0 @@
-; Disassembly of SYS; TS TTYSWP
-
-; Symbol table:
-;
-; a      = 1
-; usri  == 1
-; b      = 2
-; c      = 3
-; d      = 4
-; e      = 5
-; f      = 6
-; jcl    = 100
-; tty1   = 116
-; tty2   = 117
-; jobnum = 120
-; start  = 121
-; numget = 123
-; nextch = 131
-; doit   = 147
-; nmytty = 166
-; detme  = 223
-; getnam = 230
-; won    = 243
-; detach = 246
-; attach = 252
-; usropn = 257
-; styget = 266
-
-; Start instruction:
-;
-; jrst 121
-
-
-; Program:
-;
-; 000116:  777777777777
-; 000117:  777777777777
-; 000120:  000000000000
-; 000121:  045500000274  .break   12, 274         ;"$M  "\"
-; 000122:  200040000275  move     1, 275          ;"0 @ "]"
-; 000123:  400100000000  setz     2,              ;"@!    "
-; 000124:  134140000001  ildb     3, 1            ;"+A@  !"
-; 000125:  322140000147  jumpe    3, 147          ;":1@ !G"
-; 000126:  301140000060  cail     3, 60           ;"8)@  P"
-; 000127:  303140000071  caile    3, 71           ;"89@  Y"
-; 000130:  254000000124  jrst     124             ;"5@  !4"
-; 000131:  242100000003  lsh      2, 3            ;"41   #"
-; 000132:  275140000060  subi     3, 60           ;"7I@  P"
-; 000133:  434100000003  or       2, 3            ;"CA   #"
-; 000134:  134140000001  ildb     3, 1            ;"+A@  !"
-; 000135:  322140000147  jumpe    3, 147          ;":1@ !G"
-; 000136:  301140000060  cail     3, 60           ;"8)@  P"
-; 000137:  303140000071  caile    3, 71           ;"89@  Y"
-; 000140:  334000000000  skipa    0, 0
-; 000141:  254000000131  jrst     131             ;"5@  !9"
-; 000142:  331000000116  skipl    0, 116          ;";(  !."
-; 000143:  254000000146  jrst     146             ;"5@  !F"
-; 000144:  202100000116  movem    2, 116          ;"01  !."
-; 000145:  254000000123  jrst     123             ;"5@  !3"
-; 000146:  202100000117  movem    2, 117          ;"01  !/"
-; 000147:  200040000116  move     1, 116          ;"0 @ !."
-; 000150:  321040000223  jumpl    1, 223          ;":(@ "3"
-; 000151:  660040400000  tro      1, 400000       ;"V @@  "
-; 000152:  202040000116  movem    1, 116          ;"00@ !."
-; 000153:  043000000266  .call    [setz
-;                                  SIXBIT/STYGET/
-;                                  000000000001
-;                                  002000000120
-;                                  002000000120
-;                                  402000000120]
-; 000154:  043100001000  .lose    1000            ;"$9  ( "
-; 000155:  550040000120  hrrz     1, 120          ;"M @ !0"
-; 000156:  660040400000  tro      1, 400000       ;"V @@  "
-; 000157:  264000000230  jsr      230             ;"6@  "8"
-; 000160:  200140000001  move     3, 1            ;"0!@  !"
-; 000161:  200300000005  move     6, 5            ;"0#   %"
-; 000162:  200040000117  move     1, 117          ;"0 @ !/"
-; 000163:  325040000166  jumpge   1, 166          ;":H@ !V"
-; 000164:  043540000276  .suset   276             ;"$=@ "^"
-; 000165:  505040000000  hrli     1, 0            ;"HH@   " "Q\"\0\0\0"
-; 000166:  660040400000  tro      1, 400000       ;"V @@  "
-; 000167:  202040000117  movem    1, 117          ;"00@ !/"
-; 000170:  043000000266  .call    [setz
-;                                  SIXBIT/STYGET/
-;                                  000000000001
-;                                  002000000120
-;                                  002000000120
-;                                  402000000120]
-; 000171:  043100001000  .lose    1000            ;"$9  ( "
-; 000172:  550040000120  hrrz     1, 120          ;"M @ !0"
-; 000173:  660040400000  tro      1, 400000       ;"V @@  "
-; 000174:  264000000230  jsr      230             ;"6@  "8"
-; 000175:  200200000001  move     4, 1            ;"0"   !"
-; 000176:  200100000003  move     2, 3            ;"0!   #"
-; 000177:  306100777777  cain     2, 777777       ;"8Q ___"
-; 000200:  254000000203  jrst     203             ;"5@  "#"
-; 000201:  043000000246  .call    [setz
-;                                  SIXBIT/DETACH/
-;                                  005000000020
-;                                  400000000002]
-; 000202:  043100001000  .lose    1000            ;"$9  ( "
-; 000203:  200100000004  move     2, 4            ;"0!   $"
-; 000204:  306100777777  cain     2, 777777       ;"8Q ___"
-; 000205:  254000000213  jrst     213             ;"5@  "+"
-; 000206:  043000000246  .call    [setz
-;                                  SIXBIT/DETACH/
-;                                  005000000020
-;                                  400000000002]
-; 000207:  043100001000  .lose    1000            ;"$9  ( "
-; 000210:  200040000116  move     1, 116          ;"0 @ !."
-; 000211:  043000000252  .call    [setz
-;                                  SIXBIT/ATTACH/
-;                                  004000000005
-;                                  000000000002
-;                                  400000000001]
-; 000212:  043100001000  .lose    1000            ;"$9  ( "
-; 000213:  200040000117  move     1, 117          ;"0 @ !/"
-; 000214:  200100000003  move     2, 3            ;"0!   #"
-; 000215:  200240000006  move     5, 6            ;"0"@  &"
-; 000216:  306100777777  cain     2, 777777       ;"8Q ___"
-; 000217:  254000000222  jrst     222             ;"5@  "2"
-; 000220:  043000000252  .call    [setz
-;                                  SIXBIT/ATTACH/
-;                                  004000000005
-;                                  000000000002
-;                                  400000000001]
-; 000221:  043100001000  .lose    1000            ;"$9  ( "
-; 000222:  043200000243  .value   243             ;"$:  "C"
-; 000223:  043540000277  .suset   277             ;"$=@ "_"
-; 000224:  660100400000  tro      2, 400000       ;"V! @  "
-; 000225:  043000000246  .call    [setz
-;                                  SIXBIT/DETACH/
-;                                  005000000020
-;                                  400000000002]
-; 000226:  043100001000  .lose    1000            ;"$9  ( "
-; 000227:  043200000243  .value   243             ;"$:  "C"
-; 000230:  000000000000
-; 000231:  306040777777  cain     1, 777777       ;"8P@___"
-; 000232:  254020000230  jrst     @230            ;"5@0 "8"
-; 000233:  043000000257  .call    [setz
-;                                  SIXBIT/OPEN  /
-;                                  005000000010
-;                                  001000000001
-;                                  000000000302
-;                                  000000000001
-;                                  401000000000]
-; 000234:  043100001000  .lose    1000            ;"$9  ( "
-; 000235:  400240000000  setz     5,              ;"@"@   " "@\n\0\0\0"
-; 000236:  044040000300  .uset    1, 300          ;"$@@ # "
-; 000237:  316100000301  camn     2, 301          ;"9Q  #!"
-; 000240:  660240400000  tro      5, 400000       ;"V"@@  "
-; 000241:  042040000007  .close   1,              ;"$0@  '"
-; 000242:  254020000230  jrst     @230            ;"5@0 "8"
-
-; Data:
-;
-; 000243:  135651344630  ldb      15, 344630(11)  ;"+NI<F8" ":KILL"
-; 000244:  460327253226  setcm    6, @253226(7)   ;"F#75:6" "L\r:VK"
-; 000245:  064000000000                           ;"&@    " "\r\0\0\0\0"
-; 000246:  400000000000  setz     0,              ;"@     " "@\0\0\0\0"
-; 000247:  444564414350  eqv      13, @414350(4)  ;"DETACH"
-; 000250:  005000000020                           ;" H   0"
-; 000251:  400000000002  setz     0, 2            ;"@    ""
-; 000252:  400000000000  setz     0,              ;"@     " "@\0\0\0\0"
-; 000253:  416464414350  setmm    11, @414350(4)  ;"ATTACH"
-; 000254:  004000000005                           ;" @   %"
-; 000255:  000000000002                           ;"     ""
-; 000256:  400000000001  setz     0, 1            ;"@    !"
-; 000257:  400000000000  setz     0,              ;"@     " "@\0\0\0\0"
-; 000260:  576045560000  hlrem    1, 560000(5)    ;"OPEN  " "_B-`\0"
-; 000261:  005000000010                           ;" H   ("
-; 000262:  001000000001                           ;" (   !"
-; 000263:  000000000302                           ;"    #""
-; 000264:  000000000001                           ;"     !"
-; 000265:  401000000000  setzi    0,              ;"@(    " "@ \0\0\0"
-; 000266:  400000000000  setz     0,              ;"@     " "@\0\0\0\0"
-; 000267:  636471474564  tdzn     11, @474564(11) ;"STYGET" "gSLy:"
-; 000270:  000000000001                           ;"     !"
-; 000271:  002000000120                           ;" 0  !0"
-; 000272:  002000000120                           ;" 0  !0"
-; 000273:  402000000120  setzm    120             ;"@0  !0"
-; 000274:  000005000100                           ;"  % ! "
-; 000275:  440700000100  andcb    16, 100         ;"D'  ! "
-; 000276:  000002000001                           ;"  "  !"
-; 000277:  000023000002                           ;"  3  ""
-; 000300:  000005000002                           ;"  %  ""
-; 000301:  504143646256  hrl      3, 646256(3)    ;"HACTRN"
-; 000302:  656362000000  tdcn     7, @(2)         ;"USR   "
diff --git a/src/sysen3/ttyswp.2 b/src/sysen3/ttyswp.2
new file mode 100644
index 00000000..8701125e
--- /dev/null
+++ b/src/sysen3/ttyswp.2
@@ -0,0 +1,130 @@
+TITLE TTYSWP
+
+a=1
+b=2
+c=3
+d=4
+e=5
+f=6
+
+usri==1
+
+jcl:	block 16
+tty1:	-1
+tty2:	-1
+jobnum:	0
+
+start:	.break 12,[..rjcl,,jcl]
+	move a,[440700,,jcl]
+numget:	setz b,
+	ildb c,a
+	jumpe c,doit
+	cail 3,"0
+	 caile 3,"9
+	  jrst numget+1
+nextch:	lsh b,3
+	subi c,"0
+	ior b,c
+	ildb c,a
+	jumpe c,doit
+	cail c,"0
+	 caile c,"9
+	  skipa
+	   jrst nextch
+	    skipl tty1
+	     jrst .+3
+	movem b,tty1
+	jrst numget
+	movem b,tty2
+
+doit:	move a,tty1
+	jumpl a,detme
+	tro a,400000
+	movem a,tty1
+	.call styget
+	 .lose %lssys
+	hrrz a,jobnum
+	tro a,400000
+	jsr getnam
+	move c,a
+	move f,e
+	move a,tty2
+	jumpge a,nmytty
+	.suset [.rtty,,a]
+	hrli a,0
+nmytty:	tro a,400000
+	movem a,tty2
+	.call styget
+	.lose %lssys
+	hrrz a,jobnum
+	tro a,400000
+	jsr getnam
+	move d,a
+	move b,c
+	cain b,-1
+	jrst .+3
+	.call detach
+	 .lose %lssys
+	move b,d
+	cain b,-1
+	jrst .+6
+	.call detach
+	 .lose %lssys
+	move a,tty1
+	.call attach
+	 .lose %lssys
+	move 1,tty2
+	move b,c
+	move e,f
+	cain b,-1
+	jrst .+3
+	.call attach
+	 .lose %lssys
+	.value won
+detme:	.suset [.ruind,,b]
+	tro 2,400000
+	.call detach
+	 .lose %lssys
+	.value won
+
+getnam:	0
+	cain a,-1
+	 jrst @getnam
+	.call usropn
+	 .lose %lssys
+	setz e,
+	.uset usri,[.rjname,,b]
+	camn b,[sixbit /hactrn/]
+	 tro e,400000
+	.close usri,
+	jrst @getnam
+
+won:	asciz /:KILL
:VK
/
+
+detach:	setz
+	sixbit /detach/
+	%clbit,,20
+	setz b
+
+attach:	setz
+	sixbit /attach/
+	%clbtw,,5
+	b
+	setz a
+
+usropn:	setz
+	sixbit /open/
+	%clbit,,10
+	%climm,,usri
+	[sixbit /usr/]
+	a
+	setzi 0
+
+styget:	setz
+	sixbit /styget/
+	a
+	%clout,,jobnum
+	%clout,,jobnum
+	setzm jobnum
+
+end start