diff --git a/code/game/objects/items/devices/PDA/PDA.dm b/code/game/objects/items/devices/PDA/PDA.dm
index ccb1633d90a..6f8e9884203 100644
--- a/code/game/objects/items/devices/PDA/PDA.dm
+++ b/code/game/objects/items/devices/PDA/PDA.dm
@@ -363,7 +363,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 				dat += "<a href='byond://?src=[REF(src)];choice=Toggle Ringer'>[PDAIMG(bell)]Ringer: [silent == 1 ? "Off" : "On"]</a> | "
 				dat += "<a href='byond://?src=[REF(src)];choice=Toggle Messenger'>[PDAIMG(mail)]Send / Receive: [toff == 1 ? "Off" : "On"]</a> | "
 				dat += "<a href='byond://?src=[REF(src)];choice=Ringtone'>[PDAIMG(bell)]Set Ringtone</a> | "
-				dat += "<a href='byond://?src=[REF(src)];choice=21'>[PDAIMG(mail)]Messages</a><br>"
+				dat += "<a href='byond://?src=[REF(src)];choice=[PDA_UI_READ_MESSAGES]'>[PDAIMG(mail)]Messages</a><br>"
 				dat += "<a href='byond://?src=[REF(src)];choice=Sorting Mode'>Sorted by: [sort_by_job ? "Job" : "Name"]</a>"
 
 				if(cartridge)
@@ -388,7 +388,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 					dat += "None detected.<br>"
 				else if(cartridge?.spam_enabled)
 					dat += "<a href='byond://?src=[REF(src)];choice=MessageAll'>Send To All</a>"
-			if(6)
+			if(PDA_UI_SKILL_TRACKER)
 				dat += "<h4>[PDAIMG(mail)] ExperTrak® Skill Tracker V4.26.2</h4>"
 				dat += "<i>Thank you for choosing ExperTrak® brand software! ExperTrak® inc. is proud to be a Nanotrasen employee expertise and effectiveness department subsidary!</i>"
 				dat += "<br><br>This software is designed to track and monitor your skill development as a Nanotrasen employee. Your job performance across different fields has been quantified and categorized below.<br>"
@@ -416,7 +416,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 						if (lvl_num >= length(SKILL_EXP_LIST) && !(type in targetmind.skills_rewarded))
 							dat += "<br><a href='byond://?src=[REF(src)];choice=SkillReward;skill=[type]'>Contact the Professional [S.title] Association</a>"
 						dat += "</li></ul>"
-			if(21)
+			if(PDA_UI_READ_MESSAGES)
 				if(icon_alert && !istext(icon_alert))
 					cut_overlay(icon_alert)
 					icon_alert = initial(icon_alert)
@@ -429,7 +429,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 				dat += tnote
 				dat += "<br>"
 
-			if (3)
+			if (PDA_UI_ATMOS_SCAN)
 				dat += "<h4>[PDAIMG(atmos)] Atmospheric Readings</h4>"
 
 				var/turf/T = user.loc
@@ -544,7 +544,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 				if(!silent)
 					playsound(src, 'sound/machines/terminal_select.ogg', 15, TRUE)
 			if(PDA_UI_READ_MESSAGES)
-				ui_mode = PDA_UI_MESSENGER
+				ui_mode = PDA_UI_READ_MESSAGES
 				if(!silent)
 					playsound(src, 'sound/machines/terminal_select.ogg', 15, TRUE)
 			if(PDA_UI_ATMOS_SCAN)