This attribute specifies the maximum time the receiving Radio Link
Protocol (RLP1) entity shall wait for the peer to ACK or NAK data.
During the Exchange Information (XID) negotiation, both RLP1
entities (mobile station and IWF) can agree to use a specific value
for this timer (T3). The IWF attempts to negotiate to the value
specified by this attribute.
Changes to this attribute do not affect existing calls.