We already know that the CDMA ( Verizon ) and GSM ( AT&T and outside ) iPhones are ever - so - slightly differentphysicallyand internally — but justhowdifferent are the two iPhones in terms of genuine , literal - world usance ?
On Wednesday , Apple published a novel support written document with the tricky headlineiPhone : Understanding phone features . As it turns out , various rather mundane phone features lick differently , depending on whether you ’re using a GSM iPhone or a CDMA one .
GSM ( Global System for Mobile Communications ) and CDMA ( Code Division Multiple Access ) are two competing cellular internet standard . In the U.S. both Verizon and Sprint largely practice CDMA - based net , with AT&T and T - Mobile using GSM . Internationally , GSM is far more commonplace , with CDMA used conspicuously in only a handful of land .
Because of the two unlike web protocol , some calling features are toggled other than on the two phone . On a GSM iPhone , to grow Call furtherance , Call Waiting , and Caller ID on or off , you launch the options app , spigot Phone , and then conform the appropriate ascendance . Changing those same preferences on a CDMA telephone set , however , requires dialing particular codes—*72 , * 70 , and * 67 , severally . And for disable Call Waiting or ( outgoing ) Caller ID , you need to dial those unequaled codes every single meter you place a call .
Apple ’s new written document also highlights differences between how the two telephone set manage conference call . GSM iPhones can tolerate up to five simultaneous outcry , while CDMA iPhones top out at two simultaneous calls . The document also directs CDMA iPhone possessor to theiPhone User Guide , which spells out more limitations in CDMA ’s execution of group discussion call : you ca n’t mix calls if the second call is incoming , and you ca n’t switch between call if the second call was extroverted — though you could , in that vitrine , merge the calls . And on CDMA iPhones , if you end the 2nd call or the merged call , both vociferation are terminated . These conference call limitation are autochthonous to all Verizon CDMA phone , not just the iPhone .
Another difference highlight in Apple ’s knowledge base document is the way the two phones handle dialing pauses — a lineament you might need if , for deterrent example , you ’re dialing into an automated phone scheme . Soft pauses shape identically : you knock and hold * ( asterisk ) while dialing ; when editing a contact ’s number , you tap the + * # key and then Pause . But if you need to dial ahardpause — one where the remaining digits are n’t dialed until you pink Dial a 2d time — your only option is a CDMA iPhone , because GSM iPhones do n’t support backbreaking pauses at all . To trigger the hard break on a CDMA iPhone , you hold down # while dialing , or tap that + * # key and then take Wait when editing a tangency ’s identification number .
If you care putting your callers on Hold — as opposed to simply damp your end of the call — you’ll need a GSM iPhone . ( You tap and hold the onscreen Mute button while on a call to trigger Hold . ) CDMA networks do n’t confirm that functionality .
Apple also recognize in the document that CDMA iPhones may have issues in certain vitrine when you attempt to dial phone numbers that hold alphabetic characters if they exceed the normal ten - digit limit . The only suggest root is to manually edit the number as necessary .
So , why all these differences ? As Verizon once publicise , “ It ’s the web . ” While the two web technology achieve the same end outcome — i.e. , urinate your cellphone phone work — they do so in vastly dissimilar ways behind the scenes . CDMA networks box up data — your voice calls and your Internet utilisation — very differently from GSM phone . These call differences , much like the fact that CDMA phones do n’t endure simultaneous data usage while on the phone , are simply related to difference in the core technical makeup of the networks themselves .
Whether these career differences should influence your determination about whether to go with AT&T or Verizon for your next iPhone is , in the end , a personal decision . Obviously , if you ’re already accustomed to the limitations of one connection , you need n’t fear using the iPhone on it ; the departure Apple describes in the young document are really true for all Verizon and AT&T phones , not just the iPhone . If , on the other manus , you ’re considering a connection switch , check that you wo n’t lose a feature you rely on , like 5 - way conference calls .
presumptively , neither Apple nor its client — and probably not even Verizon — are happy with some of the limitations of CDMA networks . It ’s hard to say which of those three entities — Apple , Verizon , or consumer — is more eager for Verizon to completeits upgrade to the next - generation LTE standard , which should eliminate most of these frustration .
