HP 5000 Router manual Serial Interface Cable Synchronous and Asynchronous Mode, DTE and DCE Mode

50APPENDIX A: CABLE SPECIFICATIONS

Serial Interface Cable Synchronous and Asynchronous Mode

V.35 and V.24 (EIA/TIA-232) standards support synchronous operating mode. V.24 (EIA/TIA-232) also supports the asynchronous operating mode. The maximum transmission distance and baud rate of the signal vary with the operating mode.

Table 20 Transmission Rate and Transmission Distance of V.24 (EIA/TIA-232)/V.35 Cable

V.24 (EIA/TIA-232)			V.35
	Maximum		Maximum
	transmission		transmission
Baud rate (bps)	distance (m)	Baud rate (bps)	distance (m)
2400	60	2400	1250
4800	60	4800	625
9600	30	9600	312
19200	30	19200	156
38400	20	38400	78
64000	20	54000	60
115200	10	64000	50
-	-	2048000	30

The baud rate should not exceed 64 Kbps when the V.24 cable operates in synchronous mode.

DTE and DCE Mode

The synchronous serial interface can operate in both DTE and DCE modes. For two devices connected directly, one device should operate in DTE mode, and the other device should operate in DCE mode. The DCE device provides a synchronous clock and specifies the transmission rate, the DTE device accepts the synchronous clock and communicates at the specified transmission rate. Usually, the router serves as the DTE device. To determine whether the device is a DTE or a DCE, refer to the user manual for the device.

Table 21 Typical DTE and DCE

Type of Equipment	Type of Interface	Typical Equipment
DTE	male	PC or router
DCE	female	Modem, multiplexer or
		CSU/DSU

The asynchronous serial interface generally is connected to a modem or a terminal adapter (TA) to act as the dial-up interface. You do not need to determine if the device is DTE or DCE, you must only select the appropriate baud rate.

The synchronous/asynchronous serial port cable is connected to a DB-50 receptacle. Proper connection cable needs to be selected for the protocol applied.

Four types of synchronous/asynchronous serial port cables are available. However, these cables are optional and you must select the proper one based on your requirements when you purchase the router All these types of cables have a DB-50 adapter at one end.