Cabletron Systems 1800 - Manual (Page 410)

C-18 SmartSwitch 1800 4. 0 User G uide, Rev 01
E&M Type II
Idle Condition: The "E" lead is biased by the PBX at -48 Vdc. The "M" lead is biased
at -48 Vdc by the attached device (SmartSwitch 1800).
PBX Initiated Call: The PBX grounds the "M" lead, signaling to the attached device
that it wants a connection. The attached device grounds the "E" lead, signaling the
response.
Attached Device-Initiated Call: The attached device grounds the "E" lead, signaling
to the PBX that it wants a connection. The PBX grounds the "M" lead, signaling the
response.
PBX-Initiated Disconnect: The PBX initiates disconnection by opening the "M"
lead. The "M" lead is pulled to -48 Vdc, as biased by the attached device. In response,
the attached device opens the "E" lead, which is pulled to -48 Vdc, as biased by the
PBX.
Attached Device-Initiated Disconnect: The attached device initiates the disconnect
by opening the "E" lead. The "E" lead is pulled to -48 Vdc as biased by the PBX. In
response, the PBX opens the "M" lead, which is pulled to -48 Vdc, as biased by the
attached device.
E&M Type V
Idle Condition: The "E" lead is biased by the PBX at -48 Vdc. The "M" lead is biased
at -48 Vdc by the attached device (SmartSwitch 1800).
PBX-Initiated Call: The PBX grounds the "M" lead, signaling to the attached device
that it wants a connection. The attached device grounds the "E" lead, signaling the
response.
Attached Device-Initiated Call: The attached device grounds the "E" lead, signaling
to the PBX that it wants a connection. The PBX grounds the "M" lead, signaling the
response.
PBX-Initiated Disconnect: The PBX initiates disconnection by opening the "M"
lead. The "M" lead is pulled to -48 Vdc, as biased by the attached device. In response,
the attached device opens the "E" lead, which is pulled to -48 Vdc, as biased by the
PBX.
Attached Device-Initiated Disconnect: The attached device initiates the disconnect
by opening the "E" lead. The "E" lead is pulled to -48 Vdc as biased by the PBX. In
response, the PBX opens the "M" lead, which is pulled to -48 Vdc, as biased by the
attached device.