COURIER HIGH SPEED MODEMS
Data Rate Synchronization (&Xn)
During synchronous operations, transmit and receive clocks at both ends of the phone link control the precise timing of the data flow. The communications equipment at the remote DTE and your modem and DTE must all handle the data at the same speed.
The transmit clock timing signals setting, &Xn, determines whether the modem or DTE will generate the timing signals. For Online synchronous operations, the source for this setting must be the same on both systems. See Connection Rate (%Nn, &Nn) later in this appendix.
Most Online synchronous users will require the default setting, &X0.
&X0 | The Courier is the source of the Transmit clock timing |
| signals and sends them to your DTE over the |
| interface. The DTE rate will follow the connection rates. |
| Default. |
&X1 | The DTE is the source of the Transmit clock timing |
| signals and sends them to the Courier over the |
| interface. This setting is used typically in leased line |
| multiplexed operations. (Multiplexors divide the phone |
| channel so that the channel carries several calls at the |
| same time.) |
| The DTE ignores the Courier's clock timing signals and |
| negotiates the DTE and connection rates. |
&X2 | The Courier's Receiver clock is the source of the timing |
| signals. The signals are looped to the Transmit clock and |
| sent to your DTE over the |
| is only used in those systems that require |
| synchronization of data flowing in both directions. |
Synchronous Operations
