Multi-Tech Systems MT3334HD8 manual Rn Clear to Send Control, Sn Data Set Ready Control

MT3334HD8 User Guide

&Rn Clear to Send Control

n = 0, 1, or 2 Default: &R1

The &R command lets you control the state of the Clear to Send (CTS) signal on pin 5 of the RS-232/V.24 interface. Normally, CTS follows RTS when the modem is online. You have three choices. You can force the signal high, allow it to act normally, or set it to stay high until the modem disconnects, go low momentarily, and then go high again. The last option is useful with CBX phone systems and mainframe front ends that require CTS to act in this manner.

&R0 lets CTS act normally, that is, to follow RTS.

&R1 forces CTS high. When the modem goes online, CTS still provides flow control.

&R2 lets CTS drop on disconnect for the time set by register S24, then go high again.

&Sn Data Set Ready Control

n = 0, 1, or 2 Default: &S1

Use the &S command to control the state of the Data Set Ready (DSR) signal on the RS-232/V.24 interface. Normally, DSR follows CD. You can force the signal high; allow it to act normally; or set it to stay high until the modem disconnects, go low momentarily, and then go high again.

&S0 forces DSR high.

&S1 allows DSR to act normally, that is, to follow CD.

&S2 sets up DSR so that it drops for one second on disconnect and then comes up again. (If you want to set the drop time to something other than one second, change register S24.)

&RFn CTS/RTS Interaction Control

n = 0 or 1 Default: &RF1

In normal operation, Clear to Send (CTS) follows Request to Send (RTS) when the modem is online. In other words, if RTS goes off, CTS goes off. In some applications, however, it is necessary for CTS to operate independently of RTS.

&RF0 enables CTS to follow RTS.

&RF1 enables CTS to operate independently of the state of RTS. See the &R command for control of CTS.

&SFn DSR/CD Interaction Control

n = 0 or 1 Default: &SF0

Normally, the Data Set Ready (DSR) signal follows the Carrier Detect (CD) signal. In other words, if CD goes high, DSR goes high. In some applications, however, it may be necessary for DSR to operate independently of CD.

&SF0 enables DSR to follow CD.

&SF1 enables DSR to operate independently of CD. For control of DSR, see the &S command.

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