Apps like REDCOM Sigma Client

Here are some great alternatives to REDCOM Sigma Client by REDCOM Laboratories :
Sipnetic
Sipnetic
★4.0
Acrobits: VoIP SIP Softphone
Acrobits: VoIP SIP Softphone
★3.6
Bria Mobile: VoIP Softphone
Bria Mobile: VoIP Softphone
★4.1
Groundwire: VoIP SIP Softphone
Groundwire: VoIP SIP Softphone
★3.5
SessionTalk Pro Softphone
SessionTalk Pro Softphone
★3.5
SessionTalk Softphone
SessionTalk Softphone
★3.6
PortSIP Softphone
PortSIP Softphone
★3.7
AGEphone
AGEphone
★4.3
MizuDroid SIP VOIP Softphone
MizuDroid SIP VOIP Softphone
★4.0
SessionCloud SIP Softphone
SessionCloud SIP Softphone
★3.6
Zoiper IAX SIP VOIP Softphone
Zoiper IAX SIP VOIP Softphone
★4.4
jiPBX - SIP VOIP Softphone
jiPBX - SIP VOIP Softphone
★4.3
Connect.US
Connect.US
★4.2
VibePlus
VibePlus
★4.0
Mabrook Plazma
Mabrook Plazma
★3.5
Mobee Star
Mobee Star
★4.0