GAI-Tronics MRTI 2000 (No. PL1877A) Microprocessor Radio Telephone Interconnect Installation & Service Manual - Manual (Page 123)

117 12/10
Features
Second Line Option
The PL1877A Second Line Option (Kit No. XTI0001A) provides mobile users with the ability to answer
and originate calls on a second phone line. Note, however, that conferencing of calls between lines 1 and
2 is not supported. At any given time, the PL1877A operates on whichever line is currently selected.
When the PL1877A is idle, it defaults to line 1 being the selected line. The PL1877A automatically
selects line 2 when it detects ringing on that line while in the idle condition. Also, the mobile can
specifically command the PL1877A to select line 2 if line 1 has not been accessed (that is, if a
conversation is not occurring on line 1).
N OTE : Generally, the PL1877A’s support for attendant originated calls (calls originated from a line-
sharing telephone set) is limited to line 1. This is because the PL1877A idles on line 1 (as stated above).
Thus, unless the PL1877A has switched to line 2 for some reason (such as a mobile command), it cannot
receive the attendant access command from a line-sharing telephone set on line 2.
Answering Calls on Line 2
When the PL1877A is idle and detects ringing on line 1, it transmits a 3-second ring signal to the mobile
(if not programmed for selective signalling or direct access). The same applies for line 2; however, the
ring signal for line 2 is comprised of two bursts (1 second burst, .5 second silence, 1.5 second burst).
This difference allows the mobile to determine whether the incoming call is on line 1 or line 2.
The mobile user answers a call on line 2 in exactly the same manner as he answers a call on line 1. That
is, he uses the * (or #* or *#*) access command (possibly preceded by a multi-digit or wildcard access
prefix).
If line 2 begins ringing while a conversation is occurring on line 1 (or if line 1 begins ringing while a
conversation is occurring on line 2), the PL1877A generates a periodic, soft, high-pitched warbling tone
to the mobile. This tone is summed with the phone line audio and does not interfere with voice
communications. It alerts the mobile that the PL1877A’s other line is ringing. If the mobile wishes to
answer the other line, he must first terminate the current conversation by entering the disconnect
command (# or ## - possibly in conjunction with a multi-digit release sequence). The PL1877A
generates 6 disconnect beeps and then transmits the 3-second ring signal (if the other line is not
programmed for selective signalling or direct access).
N OTE : Selective signaling and direct access are programmable on a per-line basis. That is, you can
program the selective signaling or direct access features to operate on one, both, or neither line.
Originating Calls on Line 2
Since the PL1877A idles on line 1, the mobile user must specifically direct the PL1877A to line 2 if he
wishes to place a call on that line. This is accomplished by dialing *2* from the mobile encoder. The
mobile user can then access the PL1877A via an access command, autodial command, or redial
command. If the mobile user has not attempted to access the phone line within 30 seconds after entering
the *2* command, the PL1877A automatically reselects line 1.