V2.7 August 2009
Datasheet
Silvertel
FEATURES
•
LOW COST SLIC
Single-in-line (SIL) PBX SLIC with integral lead
frame.
Ag1110
TIP
RING
PBX
SLIC
V
IN
V
OUT
• Highly integrated, requiring a minimum of external
components.
• Constant current feed to the line, with constant
voltage fold over.
• Single +5V system side power supply.
Control and
Supervision
• 16mA minimum loop current into 2000R loop
(including telephone set).
• 600R and 900R impedance options.
• Works with a battery of up to –72V.
Figure 1: Single Channel SLIC
• Low idle power operation (20mW).
• Short circuit protection.
• Loop open function - loop off under logic control.
• On hook transmission.
DESCRIPTION
The Silver Telecom Ag1110 comprises a single
Subscriber Line Interface Circuit (SLIC) in a
single-in-line (SIL) 13 pin format. The
combination of features and packaging offers
extremely efficient use of board area, saving
significant system size and cost.
The SLIC is highly featured requiring a
minimum of external components. Functions
such as a relay driver, are provided on board
along with precision loop feed resistors.
The Ag1110 has been designed to work in
private systems where cost is a major concern
and advanced public network signalling is not
a requirement.
The system interface has been designed for
direct connection to popular codecs for both
audio and signalling.
The Ag1110 is ideal for any application where
high-density line interfacing is required, such
as Computer Telephony Integration (CTI),
Small Office Home Office (SOHO) and PABX.
© Silver Telecom 2009
V2.7 August 2009
Data Sheet
Ag1110
LOW COST PBX SLIC
1.0 Line Interfacing
As well as being in an electrically demanding
environment, the needs of different applications and
regulatory standards means that the SLIC must allow
flexibility, together with facilities to ensure robust
performance. The Ag1110 SLIC provides a complete
and flexible interface to the telephone line.
2.1 Transmit and Receive Gain.
The gain in both the transmit direction (TIP/RING to
V
OUT
) and the receive direction (V
IN
to TIP/RING) is set
to -1dB. Normally any gain adjustments required by
the user can be made by using the Codec.
2.2 The 2 Wire Impedance
.
The input impedance, Zin, of the Ag1110 SLIC is set to
600R. For countries where the line impedance is 600R
e.g. North America and the Far East, no external
adjustment is required.
For countries where an
alternative line impedance is used the Codec filter
characteristics can be programmed to give the required
matching. For countries where the impedance is 900R,
the Ag1110-900 can be used where the SLIC
impedance is internally fixed at 900R.
The Codec manufacturer will provide information on
how
Codec
programming
is
accomplished.
Programmable Codecs require information about the
transfer characteristics of the SLIC with which they are
working, which is contained in a “.CIR” netlist. A “.CIR”
netlist can be obtained by contacting either Silver
Telecom or your local representative, to allow the
Codec programming coefficients to be generated.
If a simple Codec is being used, the Ag1110 can only
accommodate countries where the line impedance is
600R (Ag1110), or 900R (Ag1110-900).
1.1 Battery Feed
The battery feed to the telephone line used by the
Ag1110 can vary between -42V and -72V. For public
network applications -48V is the most common. A
constant current is fed to the line, which is preset to
25mA.
If the loop length is such that the constant current feed
cannot be maintained, then the Ag1110 will revert to a
constant voltage source, allowing the loop to be
serviced at a reduced loop current. Typically with a
2000R loop, and -48V battery voltage, loop current is
18.5mA.
The power dissipated in the Ag1110 SLIC is internally
limited to a safe value.
1.3 Ringing
The ringing signal is provided by an external ringing
generator and is switched onto the line by the user
provided ringing relay. The coil of the ringing relay
should be connected to a positive supply voltage
(normally +5V) and the open collector driver RDO. The
relay is activated by applying a logic high to RDI. Note:
a flyback diode must be connected across the coil.
Unbalanced ringing is supported on the Ag1110 via the
use of a single external relay (with single pole
changeover). An application drawing is shown in Fig 5.
When the “off-hook” condition occurs during ringing (as
indicated when SHK produces a logic level 1), a logic
level 0 should be applied to RDI. This will deactivate
the relay, and remove the ringing signal from the line.
The SLIC will then assume it’s constant current feed
condition.
2.3 Network Balance Impedance.
The network balance impedance, Zb, is set to 600R for
the Ag1110. For countries where the network balance
impedance is 600R e.g. North America and the Far
East, no external adjustment is required. For 900R
balance the Ag1110-900 can be used. For countries
where an alternative network balance impedance is
used the Codec filter characteristics can be
programmed to give the required matching. The “.CIR”
netlist is again needed to allow the Codec
programming coefficients to be generated.
If a simple Codec is being used the Ag1110 can only
accommodate countries where the line impedance is
600R or 900R.
.
2.0 The 2-4 Wire (hybrid) Conversion.
This is also referred to as the hybrid function. The
Ag1110 transmits and receives balanced 2-wire analog
signals at the Tip and Ring connections. These are
converted to a ground referenced output at V
OUT
and
from a ground referenced input at V
IN
.
V
OUT
and V
IN
are normally connected to a Codec for
conversion to and from a digital Pulse Code Modulated
(PCM) stream.
2.5 On Hook Transmission.
The Ag1110 is capable of on-hook transmission with
the addition of a 20k, 0.25W resistor from Tip to Ring.
This means analog signals can be transmitted from V
IN
through Tip and Ring and onto the line even when no
loop current is flowing. This can be used when
sending Caller Line Identification (CLI) information or
for other “no ring” calls. With the tip-ring resistor fitted,
idle current increases by 2.2mA.
© Silver Telecom 2009
Page 5
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