| 摘要 |
<p>In a communication network, a source frame relay unit responds to a signaling message from a source terminal by determining whether a communication link has a bandwidth sufficient to transmit a sound signal at a predetermined speed in a frame relay format, and forwards the message toward a destination frame relay unit to establish a connection if the link has a bandwidth sufficient to transmit the sound signal, or returns a busy tone otherwise. Responsive to a preamble tone signal from a destination terminal, the destination frame relay unit determines whether the link has a remaining bandwidth that can support the difference between the predetermined speed of the sound signal and a speed requested by the preamble tone signal to transmit facsimile signals in the frame-relay format. If so, the source and destination terminals are allowed to exchange facsimile signals at the requested speed. Otherwise, the terminals are controlled to exchange facsimile signals at a speed lower than the requested speed. <IMAGE></p> |
