Printed in the U.S.A. ZF290950 Rev CFax Back Doc # 060
Due to the dynamic nature of the product design, the information contained in this document is subject to change without notice. Viking
Electronics, its affiliates and/or subsidiaries assume no responsibility for errors and/or omissions contained in this information. Revisions of
this document or new editions of it may be issued to incorporate such changes.

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Programming
Switch
1
2
3
4
Position
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Description
Receive line status data from the TMS-6X
Receive line status data from the TMS-12A
Ring cadence: 1 sec on, 3 sec off
Ring cadence: 2 sec on, 4 sec off
Unused
Unused (Leave in OFF position)
Unused
Unused (Leave in OFF position)
Operation
VIKING©
MODEL SQRG-12
VIKING ELECTRONICS, INC. HUDSON, WI 54016
SEQUENTIAL RING
GENERATOR
RJ21X RJ21X
J2 J1
TMS
CONTROL LINE
RESET
13.8V AC
1.25A MAX
POWER
1 2 3 4
1 2 3 4 ON
OFF
The SQRG-12 is a sequential ring generator option for use with the TMS-6X and TMS-12A. The SQRG-12 will re-ring
lines for the KSU/PABX based on line status information from the TMS-6X or TMS-12A.
The SQRG-12 is designed for applications where more than one person answers incoming calls, or in locations where
the TMS-6X or TMS-12A front panel display is not visible. The SQRG-12 eliminates confusion about which line to
answer next by only ringing the oldest call to the key system or PABX.
In some applications, it is desirable to have the SQRG-12 re-ring all calls that are ringing or holding within the call
sequencer. This is required in many PABX applications and some key system applications to prevent call crashing
(glare) problems when the C.O. lines connected to the TMS-6X or TMS-12A are also used for outgoing calls by the
PABX or KSU. The SQRG-12 is capable of this mode of operation when DIP switch 3 on the TMS-12A is in the on
position, or the TMS-6X has special software “TMS-PRAL” installed.

A. SQRG-12 Operation when Ringing Calls in Sequence

When the SQRG-12 is used with loop start C.O. lines, and you want the calls to ring through to the telephones in
sequence (one at a time), use J2 to block C.O. ringing from passing to the PABX or KSU. As a call rings in, the
TMS-6X or TMS-12A detects the ringing, and tells the SQRG-12 to ring that line through to the PABX or KSU (only if
this line is the oldest call). If a live operator does not answer, the TMS-6X or TMS-12A will answer the call, play the
message and put the caller on hold, while continuously commanding the SQRG-12 to re-ring that line into your
system. As new calls ring in on other lines, the SQRG-12 blocks these calls from ringing through to the PABX or
KSU until they have become the oldest call. Once an operator answers the oldest ringing call, the TMS-6X or TMS-
12A will begin ringing the next oldest call through to the PABX or KSU. This process of ringing calls through one at
a time will continue until the operators have answered all holding or ringing calls.

B. SQRG-12 Operation when Ringing All Calls

When the SQRG-12 is used with either loop or ground start C.O. lines, and you want all holding or ringing calls re-
rang through to the telephones, use J1 to pass tip ground (for ground start trunks), and ringing through to the PABX
or KSU. Note that the internal jumpers J1 through J12 must be removed any time you use the J1 jack. The J1 jack
is a straight through jack, so in the idle state, the C.O. tip and ring are passed straight through to the PABX or KSU.
When the TMS-6X or TMS-12A recognize that there is an incoming call on a line, the call sequencer commands the
SQRG-12 to re-ring that line along with any other lines that are ringing or holding. While the SQRG-12 is ringing a
given line position of the PABX or KSU, the SQRG-12 constantly maintains a grounded tip condition (for ground start
lines), supplies -48V DC battery on the ring side of the phone line and superimposes its high voltage ringing on this -
48V DC. This is purposely part of the SQRG-12 design to give the ground trunk card in the PABX or KSU the
impression that the line is a ringing line that has never been answered, even though the TMS-6X or TMS-12A may
be holding a call on that line. All calls will continue to ring through to the PABX or KSU until the call is answered by
a live operator, or the caller hangs up (abandons).
Although the J1 jack was designed for ground start C.O. lines, it also works properly for loop start C.O. lines when
using the “ring all lines” mode.