Patent attributes
A method and apparatus is described, by means of which a host data communication device obtains the effects of a desired data communication protocol, such as flow control, that may not be supported by a client device. To obtain the effects of the desired protocol, the host invokes a different protocol supported by the client, for example retransmission, by presenting an appropriate protocol-initiation signal, for example by asserting an error bit on a bidirectional connection to the client. Invoking the supported protocol repetitively, if necessary, the host interprets the client response to the invocation to achieve substantially the same effect as the desired protocol. Thus, a repetitive retransmission request by the host may have the effect of a flow hold request.