User`s manual

U.S. Robotics I-modem Command Reference
Analog Synchronous Applications • Page 16-3
Transmit and Receive synchronous timing pins are required at the EIA-232 interface. Pins
15 and 17 are required: The I-modem transmits timing signals through pin 15 and receives
timing signals through pin 17.
Communications Software
The devices at both ends of the link must use the same synchronous protocol.
Ask your network administrator about the software support (for example, a speciÞc com-
munications package) that you need to log into the network.
Synchronous Operations
During synchronous operations, transmit and receive clocks at both ends of the phone link
control the precise timing of the data ßow. The communications equipment at the remote
device and the I-modem and computer must all handle the data at the same speed.
The I-modem is always the source of the transmit clock timing signals and sends them to
your computer over the EIA-232 interface. Your computerÕs rate will follow the connec-
tion rates.