This attribute specifies the maximum desired ingress bit rate used
during voice traffic when voiceEncoding is g711G726.
The negotiated maximum ingress voice rate is available in
negotiatedIgRates.
maxVoiceG711G726Rate can be set to 16 only if this Voice Service
is running on a DS1V, E1V, 1pDS1V, 1pE1V or J2MV card.