Intermec EasyCoder 201 II - Ma Current Loop on Uart1; Technical Manual

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Intermec EasyCoder 201 II – Technical Manual
The 20 mA current loop interface is a single-ended, full duplex
serial interface which uses current instead of voltage to transmit
signals on a four-wire line. 20 mA current corresponds to a logical
“0” and 0 mA corresponds to a logical “1”.
Opto-couplers are used to separate the transmission line from the
internal logics of the printer and the host computer. Therefore this
interface is suitable where electrical interference may occur, and for
transmission over longer distances (up to 500 metres or 1,500 ft.).
Depending on the configuration of the connection cable between
printer and host computer, the printer can work either active (i.e.
supplying the current) or passive. A transmission speed between
300 and 9,600 baud is recommended.
20 mA Current Loop
on "uart1:"
INTERFACES, cont'd.
Continued!
P-15
RS232
CL
P-12
+5VEXT
(P-10)
6N139
6N139
IC-41
IC-41
(IC-34)
P-15
(interface select)
IC-40 & IC-41
(opto-couplers)
P-12
(external +5V)